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particle196 · 10 days

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Nanoparticles The Future of Science!

Nanoparticles are at the frontier of science and technology, offering vast potential across multiple fields due to their unique properties at the nanoscale (1 to 100 nanometers). Their small size and high surface area-to-volume ratio enable them to interact with biological systems, materials, and environments in ways that larger particles cannot, making them invaluable for innovation and discovery.

Applications of Nanoparticles

Medicine:

Targeted Drug Delivery: Nanoparticles can be engineered to carry drugs directly to specific cells, such as cancer cells, minimizing side effects and increasing treatment efficacy.

Imaging and Diagnostics: Nanoparticles can improve the precision of medical imaging techniques like MRI and CT scans. Quantum dots, for example, are fluorescent nanoparticles used for cell imaging.

Therapeutics: Nanoparticles such as gold nanoshells can be used for hyperthermia therapy, targeting and destroying cancer cells by heating them.

Energy:

Solar Cells: Nanoparticles, especially quantum dots, improve the efficiency of photovoltaic cells by enhancing light absorption and conversion of solar energy into electricity.

Battery Technology: Nanostructured materials in lithium-ion batteries enhance energy storage capacity and charging speeds.

Catalysis: Nanoparticles are being used in catalysis to increase the efficiency of reactions, including those in fuel cells.

Environmental Science:

Water Purification: Nanoparticles can filter contaminants from water, removing heavy metals, pathogens, and organic pollutants. Nanomaterials like carbon nanotubes and nanomembranes are used in filtration systems.

Pollution Control: Nanoscale catalysts can be used in air purification and wastewater treatment, breaking down pollutants into harmless substances.

Materials Science:

Nanocomposites: Incorporating nanoparticles into materials enhances their mechanical, electrical, and thermal properties. This is used in fields like aerospace, where lightweight yet strong materials are essential.

Smart Materials: Nanoparticles enable the creation of smart materials that respond to environmental changes, such as temperature or pH shifts, finding use in packaging, clothing, and construction.

Electronics and Computing:

Transistors and Semiconductors: Nanoparticles are critical in shrinking transistors in electronic devices, which increases computing power while reducing energy consumption.

Data Storage: Nanotechnology enables the development of high-density storage devices, such as those used in advanced hard drives and memory systems.

Future Potential

Nanorobotics: The future may see the development of nanorobots that can perform tasks inside the human body, such as removing clots or repairing tissues at the cellular level.

Quantum Computing: Nanoparticles are key to quantum dots and other quantum systems that could revolutionize computing by enabling processing power beyond current classical systems.

Personalized Medicine: Nanoparticles could lead to treatments tailored to individuals' genetic profiles, allowing for personalized and precise medical interventions.

Challenges

While the potential of nanoparticles is vast, challenges remain. These include:

Toxicity and Environmental Impact: Nanoparticles’ interactions with biological systems and ecosystems are not fully understood, posing risks to health and the environment.

Cost and Scalability: Producing nanoparticles in large quantities while maintaining quality is still costly and technically challenging.

Conclusion

Nanoparticles are positioned to play a transformative role in medicine, energy, environment, and technology. Their continued development promises to drive innovation across industries, making them one of the most important tools for future scientific advancements.

#youtube #sciencefather #nanotechnology #nanoscience #nanoparticles #futureofscience #materialscience #nanomedicine

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mirrikhinfratech · 14 days

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Dholera Solar Park: Allowing India to Power Its Future, Clean

Dholera Solar Park has been marked as one of the monumental projects for not just Gujarat but the whole renewable energy landscape of India. This solar park comes right to the fore of India's solar revolution as the country strives hard to achieve its ambitious clean energy target. The Solar Park will fall under the Dholera Special Investment Region and when completed, is bound to be one of the largest in the world, an important contributor toward the country's renewable energy targets.

These are proposed under the larger developments at Dholera Smart City aimed at making Dholera a truly 'green' and 'future' city by the induction of clean energy solutions coupled with modern infrastructure.

Importance of the Dholera Solar Park

Dholera Solar Park will be a beacon example of how India is moving toward renewable energy in order to cut its carbon footprint and secure supplies of energy. With its sunny state and vast tracts of land, Gujarat only presents an ideal place for solar energy projects. It has also been at the forefront in the field of renewable energy and is bound to set new standards at Dholera.

This will help reduce the quantum of greenhouse gas emitted and hence contributes to fighting against climate change. In shifting over to solar energy, instead of fossil fuel-based power generation, India will be marching on with targets of the Paris Agreement for less than 1.5 degrees Celsius rise in the world's average temperature.

Economic Benefits and Job Creation

Besides all these environmental dividends, Dholera Solar Park would definitely pay some economic dividends. Such a development comes with the direct and indirect job opportunities of thousands of people-from skilled to unskilled labor for construction and O&M purposes of the solar park.

It also acts as an investment destination, as policies are being encouraging from the Gujarat government and central agencies, and companies start coming to invest in this park from within the country and abroad. Along with it, the manufacturing units for allied industries related to solar energy, research centers, etcetera will bring economic uplifting as well.

Technological Advantages

Dholera Solar Park has embraced all the state-of-the-art modern technological innovations in the production of solar energy. Advanced photovoltaic panels installed for this park make the energy conversion from solar to electrical a matter of great efficiency. These panels are designed such that they may bear all sorts of climatic conditions of the region and ensure durability for a long period while their production of energy remains reliable.

Apart from conventional PV panels, the park considers the potentials of floating solar panels installed on water bodies, hence reducing land usage to a minimum while energy production is efficiently carried out. In this way, much valuable land will be saved and the panels are cooled down more efficiently for better performance.

A Model for Future Solar Projects

The Dholera Solar Park has been a prototype for the forthcoming future in solar energy projects, not just within India but also at global levels. This epitomizes how solar energy can be effectually tapped through integrated mechanisms on such a large scale. The park also forms part of the wider strategy of India to integrate renewables into the grid and ensure a stable and reliable supply of electricity to its booming population and economy.

Also, this would set a benchmark for PPPs in the renewable energy sector. Herein, the stakeholders-from government agencies to private companies-can show Dholera Solar Park as a case study regarding how collaboration works in successful mega-infrastructure executions.

Conclusion

Dholera Solar Park is much more than a power generation facility; instead, it symbolizes India's commitment to a sustainable future. This instinctively will make the huge capacity of the Solar Park in generating innovation and jobs a trendsetter not only for Dholera but also for opening the doors for India to emerge as a front runner in renewable energy. Projects like the Solar Park at Dholera attain paramount importance at this juncture when the world is moving toward greener energy.

#Tata Semiconductor Plant in Dholera

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jcmarchi · 1 month

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3 Questions: From the bench to the battlefield

New Post has been published on https://thedigitalinsider.com/3-questions-from-the-bench-to-the-battlefield/

3 Questions: From the bench to the battlefield

Pursuing an Undergraduate Research Opportunity Program project (or two or three) is a quintessential part of the academic experience at MIT. The program, known as UROP, allows students to be “shoulder to shoulder” with faculty, graduate students, and affiliated researchers in MIT’s labs.

Given the plethora of research options and disciplines — everything from getting a crash course in advancing quantum computing to developing neuroprosthetics — it’s no surprise that over 90 percent of undergraduates end up doing a UROP by the time they graduate.

The half-century-old program continues to evolve, adapting to student interest. Consider the experience of rising senior Alexander Edwards, a nuclear and mechanical engineering student and cadet in the Army ROTC program. The Alabama native leveraged his military training thanks to a new fellowship with the Institute for Soldier Nanotechnologies (ISN), an endeavor in which MIT, the U.S. Department of Defense (DoD), and industry partners work together to develop technologies that advance the protection, survivability, and mission capabilities of the U.S. Armed Forces. That fellowship is thanks to a gift of alumnus and ROTC graduate Aneal Krishnan ’02, who commissioned as an infantry officer in the U.S. Army. Here, Edwards and Krishnan describe the unique UROP experience and offer advice for future students.

Q: What was special about having a UROP focused on the challenges that a soldier in the field might face, such as the decades-long challenges of managing excess weight while also having proper ballistic protection?

Edwards: Having a UROP specifically designed for MIT ROTC cadets has allowed me to grow my technical skills while also helping contribute to national defense. The ISN works on an array of different interesting research projects related to defense technologies in any and every STEM discipline.

Team members collaborate on basic research to create new materials, devices, processes, and systems, and on applied research to transition promising results toward practical products useful to the war fighter. U.S. Army members at the ISN also give guidance on soldier protection and survivability needs and evaluate the relevance of research proposed to address these needs.

These collaborations help identify dual-use applications for ISN-derived technologies for firefighters, police officers, other first responders, and the civilian community at large.

Krishnan: The ISN was founded at MIT in 2002, and since its founding, the ISN’s research has been the genesis of over 140 patents, more than 50 startups, and dozens of major transitions of fieldable products. Through the MIT ROTC/ISN fellowship, the ISN benefits from the work of exceptional science and engineering students from MIT, who will also be future military leaders and can bring a real-world perspective to their work. The ROTC cadets benefit by pursuing research as part of their degree in areas in which they are passionate, and that will benefit them in their endeavors after graduation. An overarching success of this fellowship is that there is now a connection between ROTC and MIT’s DoD labs that did not exist in my time as an undergraduate. As a tangible success in this regard, in March 2024, Lt. General Maria Barrett, the commanding general of U.S. Army Cyber Command, conducted a visit at MIT coordinated by both ROTC and the ISN, further elevating the profile of the Institute amongst the DoD top brass.

Q: What was your specific project?

Edwards: My project for the past year has been related to calculating the losses on a radio-photovoltaic thermo-nuclide generator (RTG), also known as a nuclear battery.

My classmate, fellow Army ROTC cadet and fellowship recipient rising junior William Cruz, worked with nanocomputing and piezoelectric fibers to create heartbeat-sensing clothing. He and I can attest that both projects have been incredibly fulfilling, both personally and professionally.

Alongside the UROPs, Mr. Krishnan took us on a day trip in January to Washington D.C., where we were treated to a host of amazing networking opportunities at an array of organizations that seek to transition innovation out of the lab and into the front lines such as Silicon Valley Defense Group, JP Morgan, Peraton, and from In-Q-Tel, the global, not-for-profit strategic investor for the U.S. national security community and America’s allies, hosted by fellow MIT alumnus David LoBosco ’02.

Q: What lessons or takeaways did you gain from this experience? What advice might you share with other students?

Edwards: My main takeaways from all these meetings were, first, the importance of proper communication between the private sector and the government, something that has been lacking of late, and secondly, how I may be able to apply my technical background to consulting, investment, or many other fields.

Overall, I would recommend this program to future MIT ROTC cadets, and both Cadet Cruz and I are exceedingly grateful to Mr. Krishnan and the ISN for the opportunity.

Krishnan: Cadets Edwards and Cruz will now be able to share their experiences with the next class of prospective cadet researchers, thereby increasing the fellowship’s reach and impact. Future initiatives are to expand the fellowship to MIT’s Air Force and Navy ROTC programs, schedule more visits of senior military leaders to both ROTC and ISN, and connect fellowship recipients with ISN startups for career opportunities. And for my part, I’m incredibly fortunate to have met such outstanding Americans as cadets Edwards and Cruz. I’m excited to see where life takes them and hope to be a mentor along the way.

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talktoday956 · 9 months

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Revolutionizing Renewable Energy: Quantum Dot Solar Cells and Graphene Supercapacitors Lead 2023's Sustainable Power Surge

In the dynamic landscape of technological innovation, the year 2023 has proven to be a groundbreaking period for sustainable energy solutions. From cutting-edge solar technologies to revolutionary advancements in wind power, the renewable energy sector has witnessed unprecedented growth and development. This article delves into some of the most notable breakthroughs that have shaped the news in sustainable energy over the past year.

1. Solar Power Surges with Quantum Dot Technology

One of the most significant breakthroughs in solar energy comes from the integration of quantum dot technology. These tiny semiconductor particles exhibit quantum mechanical properties, allowing for enhanced light absorption and increased energy conversion efficiency. Researchers have successfully incorporated quantum dots into solar cells, pushing the boundaries of traditional photovoltaic technology. This innovation not only improves energy output but also opens the door to flexible and lightweight solar panels, making solar energy more accessible and versatile than ever before.

2. Energy Storage Revolution: Graphene Supercapacitors

The perennial challenge of storing renewable energy efficiently may soon become a thing of the past, thanks to graphene supercapacitors. Graphene, a single layer of carbon atoms arranged in a hexagonal lattice, has extraordinary electrical conductivity and mechanical strength. Scientists have harnessed these properties to develop supercapacitors that can store and release energy at unprecedented rates. This breakthrough holds the promise of overcoming the limitations of traditional batteries, providing a more sustainable and efficient solution for storing renewable energy generated from intermittent sources like solar and wind.

3. Wind Power Reinvented: Vertical Axis Turbines Take Center Stage

In the realm of wind power, 2023 has seen a paradigm shift with the rise of vertical axis wind turbines (VAWTs). Unlike traditional horizontal axis turbines, VAWTs are designed to harness wind energy from any direction, making them more adaptable to diverse environments. This innovation not only increases energy capture efficiency but also addresses concerns about the visual impact and noise associated with conventional wind turbines. As vertical axis turbines gain momentum, they are poised to redefine the future of wind energy and contribute to a more sustainable and aesthetically pleasing energy landscape.

4. Hydrogen Fuel Cells Reach Commercial Viability

Hydrogen fuel cells have long been touted as a clean energy solution, but their widespread adoption faced challenges related to cost and efficiency. In 2023, significant strides have been made to overcome these hurdles, with hydrogen fuel cells now reaching commercial viability. Advancements in catalyst materials and manufacturing processes have led to more efficient and affordable fuel cells, offering a promising alternative for various applications, from powering electric vehicles to providing backup power for homes and industries on yahoo.

5. AI-Powered Energy Management Systems

Artificial Intelligence (AI) has emerged as a key player in optimizing energy consumption and enhancing overall energy efficiency. AI-powered energy management systems analyze vast amounts of data in real-time to optimize energy usage, predict demand patterns, and streamline energy distribution. This technology not only contributes to reducing energy waste but also empowers consumers and businesses to make informed decisions about their energy consumption. As smart grids and AI-driven energy solutions become more prevalent, the transition towards a sustainable and intelligent energy ecosystem gains momentum.

Conclusion:

The year 2023 has undeniably been a pivotal year for sustainable energy, marked by groundbreaking developments across various technologies. From quantum dot-enhanced solar cells to graphene supercapacitors and innovative wind turbine designs, these advancements are propelling the renewable energy sector into a new era. Moreover, the commercial viability of hydrogen fuel cells and the integration of AI in energy management signify a holistic approach towards a cleaner and more efficient energy future.

As we celebrate these achievements, it is crucial to recognize that the journey towards a sustainable energy landscape is ongoing. Continued research, investment, and global collaboration will be essential to address the challenges ahead and ensure a brighter, greener future for generations to come. The developments of 2023 serve as a testament to the potential and promise of sustainable energy, inspiring optimism for what lies ahead in the pursuit of a more environmentally conscious world.

#on yahoo\

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latestnew1 · 11 months

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Breakthrough Discovery Unveils New Era in Renewable Energy Generation

In a remarkable turn of events, scientists and researchers have recently made a groundbreaking discovery that promises to revolutionize the renewable energy sector. This latest news, which has the potential to reshape our approach to sustainable energy generation, comes at a time when the world is actively seeking cleaner and more efficient alternatives to fossil fuels.

The Innovation:

The focal point of this game-changing innovation lies in the realm of "Quantum Dot Solar Cells." This emerging technology represents a remarkable leap forward in the world of photovoltaics, pushing the boundaries of energy efficiency and sustainability. Quantum dots are nano-sized semiconductor particles that possess unique quantum mechanical properties, which allow for more efficient capture and utilization of solar energy.

Key Advantages:

Enhanced Efficiency: Quantum dot solar cells are poised to significantly boost the efficiency of solar panels. Unlike conventional solar cells, quantum dots can capture a broader spectrum of sunlight, including infrared and ultraviolet wavelengths, ensuring a higher energy yield.

Cost-Effective Manufacturing: The production of quantum dot solar cells is expected to be more cost-effective than traditional silicon-based solar panels. This affordability could lead to increased adoption in the residential, commercial, and industrial sectors.

Improved Environmental Footprint: By harnessing sunlight more efficiently, quantum dot solar cells reduce the reliance on fossil fuels and mitigate greenhouse gas emissions, aligning with global efforts to combat climate change.

Versatility: Quantum dots can be incorporated into various materials, including paints, plastics, and windows, expanding their application beyond conventional solar panels.

Progress and Potential:

While quantum dot solar cells are still in the research and development phase, the results thus far have been highly promising. Several research teams across the world are working fervently to scale up production and enhance the technology's reliability and longevity.

The potential implications of this innovation are vast, from powering homes and businesses more sustainably to enabling portable solar-charged devices with unprecedented efficiency. Furthermore, this development could potentially accelerate the transition to a clean energy future, reducing our dependence on finite fossil fuels.

Challenges and Considerations:

As with any emerging technology, there are challenges to overcome. Researchers must address issues related to the stability and scalability of quantum dot solar cells. Additionally, environmental and health considerations during the manufacturing and disposal of quantum dots need careful attention.

In Conclusion:

The discovery of quantum dot solar cells represents a pivotal moment in the quest for cleaner, more efficient energy sources. While there is still much work to be done, the potential for this innovation to reshape our energy landscape is undeniable. As researchers continue to make strides in this field, the prospect of a greener and more sustainable future becomes increasingly tangible. This breakthrough paves the way for a world where renewable energy plays a more dominant role in meeting our energy needs.

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sg-physics-tuition · 1 year

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Fascinating Applications of Physics: Exploring Real-World Examples in Physics Tuition

What do you think most students feel when they hear the term “Physics?” While some students love the subjects from their very core, most students dread Physics due to obvious reasons. Those who love physics understand the building blocks of the subject and some might also be intrigued with the connection of Physics with the physical and cosmic universe. However, most students fail to understand the subject beyond these theoretical and numerical parameters. They fail to comprehend the applications of Physics beyond textbooks and classrooms, how it influences technology, how it’s related to the universe, and more. That’s when an A-level physics tuition can help! How?

Well, Physics tuition isn't just about memorising equations; it's about delving into the real-world applications that make this subject truly intriguing. So, in case you are still confused about finding the best Physics tuition in Singapore, let’s explore some captivating real-world examples that showcase the practical applications of physics in various domains.

Quantum Computing: Pushing the Boundaries of Computation

Quantum physics has led to the development of a revolutionary technology: quantum computers. These devices leverage the principles of superposition and entanglement to perform complex calculations at speeds that were previously inconceivable. With the aid of a seasoned physics tutor, students can delve into quantum mechanics and understand how this cutting-edge technology holds the promise for solving problems that are currently beyond the capabilities of classical computers.

Medical Imaging: Seeing Inside with Precision

Medical imaging techniques like MRI (Magnetic Resonance Imaging) and CT (Computed Tomography) scans have revolutionised healthcare. These techniques rely on principles of physics to create detailed images of the human body's internal structures. Understanding the physics behind these imaging methods with IP physics tuition can enhance students' comprehension of their applications and significance in diagnosing and treating various medical conditions.

Renewable Energy: Tapping into Natural Resources

Physics plays a pivotal role in harnessing renewable energy sources. Solar panels, for instance, use the photovoltaic effect to convert sunlight into electricity. Wind turbines transform the kinetic energy of moving air into usable power. A physics tutor can offer insights into the underlying principles of these technologies, fostering an understanding of how we can reduce our dependence on non-renewable resources.

Space Exploration: Unravelling the Cosmos

The field of astrophysics showcases the union between theoretical physics and space exploration. Concepts like gravitational waves, black holes, and the expansion of the universe are rooted in physics principles. When you go for a physics tutor who can introduce students to astrophysics, it not only instils an appreciation for the cosmos but also highlights how physics enables us to unravel its mysteries.

Nanotechnology: The Science of the Minuscule

Nanotechnology involves manipulating matter at the nanoscale to create new materials and devices with remarkable properties. Understanding physics at this scale is crucial for designing and engineering nanoscale structures. Physics tutors can cover topics like quantum mechanics that provide a foundation for grasping the behaviour of particles and forces at this level, essential for advancements in fields like materials science and electronics.

Still, searching for the best tutors in Singapore? Go for JC Physics tuition now!

Source: https://physicstutorinsingapore.blogspot.com/2023/09/fascinating-applications-of-physics.html

#best Physics tuition in Singapore

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cherylkim23 · 2 years

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Nanosilicon and Its Applications

нанокремний has many potential applications. It can be used for smart devices. For example, it can be a component in photovoltaics. Other applications include biomedical sensing and theranostics. Silicon is also useful for abiotic stress mitigation. In addition, it can help promote plant growth and photosynthetic efficiency. There are several nanosilicon-based materials that can be used to produce photodetectors, hydrogen generation from water, and photovoltaics.

The main application of nanosilicon is in semiconductors. Nanosilicon can be integrated with other nanomaterials to improve their performance. For example, silicon can be added to the surface of polymer composites to enhance their ability to conduct electricity. Another nanosilicon application is in photodynamic therapy. Photodynamic therapy can use the blue-shifting of photoluminescence on nanosilicon to enhance the recombination of electron-hole pairs. This effect is a result of the trapped electron by the Si-O bond.

Silicon is an ideal pozzolanic material. This is a type of nanoparticle that exhibits a high specific surface area and has an excellent abiotic activity. Unlike conventional particles, it can be regenerated in the environment. Moreover, it is able to perform better with lower levels of impurities.

However, nanosilicon does not possess all of the properties that traditional polysilicon has. It has a very low band gap, which is around 3 nm. Nevertheless, it can be manipulated with quantum effects. These effects can be utilized in the nanosilicon to control the energy level. To do so, the breaking symmetry and quantum confinement of the system are used. Specifically, the quantum confinement affects the emission wavelength while the breaking symmetry affects the energy levels.

The size of the nanosilicon and the CS and QC effect play a significant role in the formation of localized states. However, the size effect is often submerged by the CS effect. A detailed calculation was performed to examine the effects of size, CS and QC on the levels of localized states.

The study shows that the size of the nanosilicon plays a crucial role in the CS effect. When the structure of the nanosilicon has too small bonds and Si-H bonds, the QD structure may enter the band gap. On the other hand, the shape of the nanosilicon is more essential to the localized state. Therefore, the size of the bonding cover, the curvature radius of the surface and the face bonding cover are all important parameters.

Among the CS and QC effects, the CS effect is the most significant. According to the study, the CS effect affects the energy levels of the impuritied QDs that contain Si atoms. The CS effect is also associated with the inverse physical mechanism. As a result, the resulting localized states of the QD with 147 Si atoms become almost nonexistent. By contrast, the QC effect fails for nanosilicon with a smaller size.

Lastly, the CS and QC effect can be coupled. In the case of the CS effect, the underlying symmetric structure of the nanosilicon is broken by the impurities. When the symmetry of the nanosilicon is broken, the emission wavelength becomes longer and the recombination rate increases.

#cherylkim23

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businessmanagement0718 · 3 years

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Building Management Techniques

Most of the automation system is behind the scenes as hardware units mounted to tools or hidden underfloor or within the ceiling. From a central management perspective, the BAS resides as software program on an operator workstation or is on the market as an online page. Early management systems had been pneumatic or air-based and have been generally restricted to controlling numerous aspects of the HVAC system.

Older techniques had been used to easily management the HVAC functionalities, the inspiration of all buildings’ vitality use. Nowadays, we can monitor and management every little thing that relates to the building’s mechanical, electrical, and plumbing techniques. These systems are composed of sensors which measure temperature, humidity, outdoors temperature, and rather more. Aside from sensors, controllers manage the operation of the tools monitored, including chillers, boilers, roof prime items, fan coil items, warmth pumps, variable air quantity packing containers, and air dealing with models. System - can successfully integrate, set up and preserve constructing management systems and provide life cycle help for services like yours, making it easier to extend consolation, security and security on your occupants. Next generation EcoStruxure Building is The Open Innovation Platform of Buildings – a collaborative Internet of Things solution that's scalable, secure and global to create future-ready sensible buildings.

Collectively, DDC merchandise management numerous constructing systems and form the automation system. Built on the SmartX IP Controller- RP-C, a modular BACnet/IP Controller, the Connected Room Solution provides a versatile structure and delivers engaging environments with personalized comfort and increased operational and power efficiency. Easily integrate with IoT gadgets, a requirement in today’s related world, while future-proofing your investment lighting control with an infrastructure that may develop with you and adapt to a constructing tenants altering wants. The Communications Automation System lays the high-speed framework for exchanging voice, knowledge and video within the constructing and to the surface world. Important parts of the system embrace PABX, complete building integration cablings, broadband Internet access and CATV connections, and public address systems.

Typically, such control systems are put in in new buildings or as a half of a renovation where they substitute an outdated management system. Reach out to our customer team in your nation or region in case you have any questions or want more details or technical assist. Building Management System, TAC I/A Series, permits you full constructing access, control and monitoring from anywhere on the earth.

CCMS can improve the general administration and performance of constructing considerably For example, the program may be designed to begin out and cease completely different gear mechanically based on a pre-determined schedule. In a more refined building management system, the CCMS can carry out interactive calculations to discover out probably the most efficient operating circumstances by bearing in mind cooling plant format, the variety of sequence and parallel chillers etc. Next, discover our energy and sustainability providers, together with big knowledge administration, to turn this imaginative and prescient into your corporation reality. Application-specific room controllers provide the control of DDC methods with the user-friendliness of thermostats.

Generates renewable vitality from sunlight by way of Cadmium Telluride nano thin-film photovoltaic know-how. The quantum dot nano top coating system decomposes PM2.5 and risky natural compounds. The system's self-cleansing impact keeps the glass surface clean, lowering the upkeep cost.Click hereto watch the video. Active systems check with the electrical and mechanical methods, such as the HVAC techniques and lighting systems.

We provide a broad range of power saving options, vitality environment friendly merchandise, power management and monitoring system, in addition to building administration system for new and present buildings. Our compact building management options are specifically designed to enhance company management efficiency and cost effectiveness, in each business surroundings. Manage enterprise operations with smart automation expertise, enhance productiveness with decreased power consumption and prices.

If you are interested in our constructing asset management solutions, contact us today to send your enquiry. Each sensible constructing contributes to this overarching goal and works towards reducing the carbon footprint of our whole society. There are additionally more tangible solutions that contribute to making smart buildings like Smart Charge, which assist reduce your carbon footprint by making electrical autos more handy by installing extra charging points. Whether your small business is helping develop new buildings or already owns a quantity of, having efficient asset administration is significant in relation to maximising profits and minimising environmental impacts.

Optimizing consolation through energy effectivity delivers a memorable buyer experience while maximizing your return on funding. If airport engineers, operators and maintenance employees had been required to study each system, the sheer magnitude of the task would require additional employees.Task sharing and rotation to cowl for sickness and holidays could be almost unimaginable. The Fire Automation System is supported by independent community and cabling techniques to ensure operation continues nonstop, even throughout an emergency. When linked to the constructing's centralized control room, a second stage of monitoring is provided; and in case of fire, various techniques can interact on to optimize all essential constructing amenities. A high temperature cooling system doesn't have to overcool the air to achieve the comfort humidity stage, thus saving vitality for air-con. The excessive temperature cooling system contains underfloor displacement cooling, radiant cooling and desiccant dehumidification.

Power is also regenerated when the carry is in up-operation with no / little load or down-operation with full / heavy load. By the radiant cooling effect, related experience of “coolness” in caves is created within the inside house. Conditioned air is supplied to the room at low level and low velocity via the floor plenum.

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materialsscienceandengineering · 3 years

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Study of promising photovoltaic material leads to discovery of a new state of matter

Researchers at McGill University have gained new insight into the workings of perovskites, a semiconductor material that shows great promise for making high-efficiency, low-cost solar cells and a range of other optical and electronic devices.

Perovskites have drawn attention over the past decade because of their ability to act as semiconductors even when there are defects in the material's crystal structure. This makes perovskites special because getting most other semiconductors to work well requires stringent and costly manufacturing techniques to produce crystals that are as defect-free as possible. In what amounts to the discovery of a new state of matter, the McGill team has made a step forward in unlocking the mystery of how perovskites pull off this trick.

"Historically, people have been using bulk semiconductors that are perfect crystals. And now, all of a sudden, this imperfect, soft crystal starts to work for semiconductor applications, from photovoltaics to LEDs," explains senior author Patanjali Kambhampati, an associate professor in the Department of Chemistry at McGill. "That's the starting point for our research: How can something that's defective work in a perfect way?"

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nonstem · 5 years

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Quantum Mechanics is Weirder and Cooler Than You Think

Introduction

Quantum mechanics has to be one of the most interesting branches of science because it encompasses phenomena that is reality-defying and appear unreal and mysterious. We live everyday life in a macroscopic world where our daily experiences have shaped our knowledge and intuition about the laws of physics, giving us the ability to predict the future. Unfortunately, when things get infinitesimally small, they don't behave as we’d expect them to. In fact, they behave so differently that there is an entire field of physics dedicated to explaining this. One main challenge with quantum mechanics is that since we can’t physically observe things at the quantum scale either, we can’t develop much intuition either which adds another barrier to a thorough understanding. Despite this, scientists have been able to make a lot of progress in understanding how quantum mechanics works through the use of experimentation and mathematical modeling. Here is a brief introduction to quantum mechanics that explains some of the fundamental concepts that govern this field.

All of quantum mechanics is built on the concept of wave-particle duality which basically states that when matter gets small enough, it begins to exhibit wave-like and particle-like behavior. In order to explain what this means, we need to look towards the double-slit experiment which demonstrates this unique and mysterious property and also propagated the remainder of quantum mechanics research.

Double-Slit Experiment

The double-slit experimental setup is comprised of a wall with two slits cut out within the middle region of the wall and a screen is placed behind the wall which will measure what passes through. Throughout the experiment, macroscopic bullets, water waves, and electrons will be emitted and the pattern that is developed on the screen will be investigated.

For trial 1, bullets will be shot and the pattern will be recorded. The resulting pattern looks like a bullet spread where towards the center of the slits openings, the bullets are most likely to be found (the peak of the humps). There are only two bands present with using bullets which demonstrate the bullet-like behavior. Nothing too special here with trial 1.

Trial 1. Bullets Demonstrating Particle-like Behavior

For trial 2, water waves will be emitted and once again the pattern will be recorded. The resulting pattern is an interference pattern that is caused by constructive and destructive interference of waves. Since the initial wave that is emitted is propagated into two smaller waves at the slit openings, the new waves interact with each other, basically adding and subtracting to form the resulting pattern that is observed. Once again, the areas near the slit openings have the highest probability distribution. There are several bands in this pattern which once again demonstrates the wave-like behavior. Nothing too special here with trial 2.

Trial 2. Wave-like Behavior

For trial 3, quantum sized matter, such as electrons, will be emitted towards the wall and the pattern will be recorded. When electrons are emitted, the resulting pattern demonstrates the same wave-like behavior observed in trial 2. Now where things begin to get interesting, when we close one of the slits and leave the other alone, we observe the same bullet-like behavior witnessed in trial 1. So how is it possible that we are able to observe a bullet-like and wave-like behavior with electrons depending on the number of slits that are open? Why does closing one slit and leaving the other open cause this contradiction?

Trial 3. Electrons With Both Slits Open

Trial 3. Electron With Only One Slit Open

To investigate this paradox, let’s take this experiment a step further and place an electron detector at one of the slits and leave the other slit open and alone and record the pattern. The electron detector will tell us if electrons are going through the slit it is positioned at. It turns out that the resulting pattern looks exactly like a bullet-spread. For some weird reason, when we observe the system, (in this case, the electron detector is physically observing if an election passes the slit it is monitoring) particle-like behavior develops, but when no observation is made (no electron detector), the pattern developed is wave-like.

Trial 3. Electrons With Detector

Discussion

In quantum mechanics, we utilize something called the wave function, which is responsible for describing all the possible states which an electron can exist in, in a given system. In this experiment, there are only two possible states for the electron to exist in since there are only two slits available. While no observation is made, the wave-like behavior is demonstrated. The peaks seen in a wave-like pattern are essentially the “probabilities” of where the electron can be found, where the fatter the peak, the more likely the electron is to be found there. The key thing to note is that this pattern can only exist if the electron travels through both slits simultaneously because otherwise, diffraction could not occur so there would be interference pattern to begin with. Yes, the electron exists in both states (it has traveled through both slits) at the same time. If we were to shoot a single electron at a time, you guessed it, we would still see wave-like pattern. I know this is crazy but this was experimentally proven.

Trial 3. Electron Wave Probabilities

What made things even more weirdness and counter-intuitive was when we place an observing agent and spied on one of the slits. If we shoot electrons at the experimental setup and quickly turn on the electron detector, we would notice a change in pattern from wave-like to particle-like behavior. The very act of observing the system affected the system to the point where it caused the wave function to collapse and force the electron to make a move. It’s almost as if the electron has already predicted its future before we even made the observation. If you shoot a million electrons at the setup with the electron detector turned on, 50% of the time the electron would go through the top slit and vice versa.

Applications

Scientists and engineers have utilized the properties of quantum mechanics in developing technology that has had major impact on society. First, one of the most significant technological advancements in history is the solid-state transistor which is used in everyday electronics. This technology utilizes electron transport and superposition of states that gives rise to their “on and off” functionality. Next, many spectroscopies and imaging techniques such as Raman Spectroscopy, Nuclear Magnetic Resonance Spectroscopy, and Scanning Electron Microscopy utilize quantum mechanical interactions with materials to understand their chemical properties and also to image materials that cannot be seen with a regular microscope. In addition, quantum mechanics has also allowed for computation and modeling which is one of the most important fields in research. This allows for scientists to conduct theoretical quantum mechanical experiments and design novel materials. Lastly, some newer applications of quantum mechanics includes photovoltaics (solar cells) and quantum computing which are hot topics in research and development today. Solar cell research is directed towards achieving better efficiencies in energy conversion while using abundant and cost-effective materials. Quantum computing research is directed towards building the first fully-functional quantum computer to run simulations that would normally take anywhere from months to years to due the limited speed that is seen with the fastest performing computer today.

Transistors on Chip

Quantum Computer

Solar Panel

Scanning Electron Microscopy Image

Conclusions

A lot of these concepts presented are pretty unintuitive and difficult to grasp because quantum mechanics is it’s own field on its own that is full of reality-defying concepts. In order to truly begin mastering quantum, you have to ditch any previous knowledge of physics and look at this material with a fresh lens because quantum behave so dissimilar to anything most have experienced and making any sort of intuition might be misleading. We know that this phenomena exists because it has been experimentally proven but our understanding of why these things happen is limited. Even to this day, no one really knows why observing a system causes a shift from wave-like to particle-like behavior. There are theories on why this could have happened (see quantum entanglement), but there is still work needed to be done in order to crack this seemingly unsolvable mystery.

I hope you were able to learn a thing or two about quantum mechanics.

#stem #quantum #chemistry #engineering #physics

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fumpkins · 4 years

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New discovery settles long-standing debate about photovoltaic materials

Ames Laboratory scientists discovered evidence of the Rashba effect by using extremely strong and powerful bursts of light firing at trillions of cycles per second to switch on or synchronize a “beat” of quantum motion within a material sample; and a second burst of light to “listen” to the beats, triggering an ultrafast receiver to record images of the oscillating state of matter. Credit: US Department of Energy, Ames Laboratory

Scientists have theorized that organometallic halide perovskites— a class of light harvesting “wonder” materials for applications in solar cells and quantum electronics— are so promising due to an unseen yet highly controversial mechanism called the Rashba effect. Scientists at the U.S. Department of Energy’s Ames Laboratory have now experimentally proven the existence of the effect in bulk perovskites, using short microwave bursts of light to both produce and then record a rhythm, much like music, of the quantum coupled motion of atoms and electrons in these materials.

Organometallic halide perovskites were first introduced in solar cells about a decade ago. Since then, they have been studied intensely for use in light-harvesting, photonics, and electronic transport devices, because they deliver highly sought-after optical and dielectric properties. They combine the high energy conversion performance of traditional inorganic photovoltaic devices, with the inexpensive material costs and fabrication methods of organic versions.

Research thus far hypothesized that the materials’ extraordinary electronic, magnetic and optical properties are related to the Rashba effect, a mechanism that controls the magnetic and electronic structure and charge carrier lifetimes. But despite recent intense study and debate, conclusive evidence of Rashba effects in bulk organometallic halide perovskites, used in the most efficient perovskite solar cells, remained highly elusive.

Ames Laboratory scientists discovered that evidence by using terahertz light, extremely strong and powerful bursts of light firing at trillions of cycles per second, to switch on or synchronize a “beat” of quantum motion within a material sample; and a second burst of light to “listen” to the beats, triggering an ultrafast receiver to record images of the oscillating state of matter. This approach overcame the limitations of conventional detection methods, which did not have the resolution or sensitivity to capture the evidence of the Rashba effect hidden in the material’s atomic structure.

“Our discovery settles the debate of the presence of Rashba effects: They do exist in bulk metal halide perovskite materials.” said Jigang Wang, senior scientist at Ames Laboratory and professor of physics at Iowa State University. “By steering quantum motions of atoms and electrons to engineer Rashba split bands, we achieve a significant leap forward for the fundamental discovery of the effect which had been hidden by random local fluctuations, and also open exciting opportunities for spintronic and photovoltaic applications based on quantum control of perovskite materials.”

The research is further discussed in the paper, “Ultrafast Control of Excitonic Rashba Fine Structure by Phonon Coherence in the Metal Halide Perovskite CH3NH3PbI3,” authored by Z. Liu, C. Vaswani, X. Yang, X. Zhao, Y. Yao, Z. Song, D. Cheng, Y. Shi , L. Luo, D.-H. Mudiyanselage, C. Huang, J.-M. Park, R.H.J. Kim, J. Zhao,Y. Yan, K.-M. Ho, and J. Wang; and published in Physical Review Letters.

Wang and his collaborators at Ames Laboratory and Iowa State University Department of Physics and Astronomy were responsible for terahertz quantum beat spectroscopy, model building, and density functional theoretical simulations. High quality perovskite materials were provided by the University of Toledo. Phonon spectra simulations were performed at the University of Science and Technology of China.

Scientists directly observe light-to-energy transfer in new solar cell materials

More information: Z. Liu et al. Ultrafast Control of Excitonic Rashba Fine Structure by Phonon Coherence in the Metal Halide Perovskite CH3NH3PbI3, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.124.157401

Provided by Ames Laboratory

Citation: New discovery settles long-standing debate about photovoltaic materials (2020, April 17) retrieved 19 April 2020 from https://phys.org/news/2020-04-discovery-long-standing-debate-photovoltaic-materials.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

New post published on: https://livescience.tech/2020/04/19/new-discovery-settles-long-standing-debate-about-photovoltaic-materials/

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jcmarchi · 10 months

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Celebrating five years of MIT.nano

New Post has been published on https://thedigitalinsider.com/celebrating-five-years-of-mit-nano/

Celebrating five years of MIT.nano

There is vast opportunity for nanoscale innovation to transform the world in positive ways — expressed MIT.nano Director Vladimir Bulović as he posed two questions to attendees at the start of the inaugural Nano Summit: “Where are we heading? And what is the next big thing we can develop?”

“The answer to that puts into perspective our main purpose — and that is to change the world,” Bulović, the Fariborz Maseeh Professor of Emerging Technologies, told an audience of more than 325 in-person and 150 virtual participants gathered for an exploration of nano-related research at MIT and a celebration of MIT.nano’s fifth anniversary.

Over a decade ago, MIT embarked on a massive project for the ultra-small — building an advanced facility to support research at the nanoscale. Construction of MIT.nano in the heart of MIT’s campus, a process compared to assembling a ship in a bottle, began in 2015, and the facility launched in October 2018.

Fast forward five years: MIT.nano now contains nearly 170 tools and instruments serving more than 1,200 trained researchers. These individuals come from over 300 principal investigator labs, representing more than 50 MIT departments, labs, and centers. The facility also serves external users from industry, other academic institutions, and over 130 startup and multinational companies.

A cross section of these faculty and researchers joined industry partners and MIT community members to kick off the first Nano Summit, which is expected to become an annual flagship event for MIT.nano and its industry consortium. Held on Oct. 24, the inaugural conference was co-hosted by the MIT Industrial Liaison Program.

Six topical sessions highlighted recent developments in quantum science and engineering, materials, advanced electronics, energy, biology, and immersive data technology. The Nano Summit also featured startup ventures and an art exhibition.

Watch the videos here.

Seeing and manipulating at the nanoscale — and beyond

“We need to develop new ways of building the next generation of materials,” said Frances Ross, the TDK Professor in Materials Science and Engineering (DMSE). “We need to use electron microscopy to help us understand not only what the structure is after it’s built, but how it came to be. I think the next few years in this piece of the nano realm are going to be really amazing.”

Speakers in the session “The Next Materials Revolution,” chaired by MIT.nano co-director for Characterization.nano and associate professor in DMSE James LeBeau, highlighted areas in which cutting-edge microscopy provides insights into the behavior of functional materials at the nanoscale, from anti-ferroelectrics to thin-film photovoltaics and 2D materials. They shared images and videos collected using the instruments in MIT.nano’s characterization suites, which were specifically designed and constructed to minimize mechanical-vibrational and electro-magnetic interference.

Later, in the “Biology and Human Health” session chaired by Boris Magasanik Professor of Biology Thomas Schwartz, biologists echoed the materials scientists, stressing the importance of the ultra-quiet, low-vibration environment in Characterization.nano to obtain high-resolution images of biological structures.

“Why is MIT.nano important for us?” asked Schwartz. “An important element of biology is to understand the structure of biology macromolecules. We want to get to an atomic resolution of these structures. CryoEM (cryo-electron microscopy) is an excellent method for this. In order to enable the resolution revolution, we had to get these instruments to MIT. For that, MIT.nano was fantastic.”

Seychelle Vos, the Robert A. Swanson (1969) Career Development Professor of Life Sciences, shared CryoEM images from her lab’s work, followed by biology Associate Professor Joey Davis who spoke about image processing. When asked about the next stage for CryoEM, Davis said he’s most excited about in-situ tomography, noting that there are new instruments being designed that will improve the current labor-intensive process.

To chart the future of energy, chemistry associate professor Yogi Surendranath is also using MIT.nano to see what is happening at the nanoscale in his research to use renewable electricity to change carbon dioxide into fuel.

“MIT.nano has played an immense role, not only in facilitating our ability to make nanostructures, but also to understand nanostructures through advanced imaging capabilities,” said Surendranath. “I see a lot of the future of MIT.nano around the question of how nanostructures evolve and change under the conditions that are relevant to their function. The tools at MIT.nano can help us sort that out.”

Tech transfer and quantum computing

The “Advanced Electronics” session chaired by Jesús del Alamo, the Donner Professor of Science in the Department of Electrical Engineering and Computer Science (EECS), brought together industry partners and MIT faculty for a panel discussion on the future of semiconductors and microelectronics. “Excellence in innovation is not enough, we also need to be excellent in transferring these to the marketplace,” said del Alamo. On this point, panelists spoke about strengthening the industry-university connection, as well as the importance of collaborative research environments and of access to advanced facilities, such as MIT.nano, for these environments to thrive.

The session came on the heels of a startup exhibit in which eleven START.nano companies presented their technologies in health, energy, climate, and virtual reality, among other topics. START.nano, MIT.nano’s hard-tech accelerator, provides participants use of MIT.nano’s facilities at a discounted rate and access to MIT’s startup ecosystem. The program aims to ease hard-tech startups’ transition from the lab to the marketplace, surviving common “valleys of death” as they move from idea to prototype to scaling up.

When asked about the state of quantum computing in the “Quantum Science and Engineering” session, physics professor Aram Harrow related his response to these startup challenges. “There are quite a few valleys to cross — there are the technical valleys, and then also the commercial valleys.” He spoke about scaling superconducting qubits and qubits made of suspended trapped ions, and the need for more scalable architectures, which we have the ingredients for, he said, but putting everything together is quite challenging.

Throughout the session, William Oliver, professor of physics and the Henry Ellis Warren (1894) Professor of Electrical Engineering and Computer Science, asked the panelists how MIT.nano can address challenges in assembly and scalability in quantum science.

“To harness the power of students to innovate, you really need to allow them to get their hands dirty, try new things, try all their crazy ideas, before this goes into a foundry-level process,” responded Kevin O’Brien, associate professor in EECS. “That’s what my group has been working on at MIT.nano, building these superconducting quantum processors using the state-of-the art fabrication techniques in MIT.nano.”

Connecting the digital to the physical

In his reflections on the semiconductor industry, Douglas Carlson, senior vice president for technology at MACOM, stressed connecting the digital world to real-world application. Later, in the “Immersive Data Technology” session, MIT.nano associate director Brian Anthony explained how, at the MIT.nano Immersion Lab, researchers are doing just that.

“We think about and facilitate work that has the human immersed between hardware, data, and experience,” said Anthony, principal research scientist in mechanical engineering. He spoke about using the capabilities of the Immersion Lab to apply immersive technologies to different areas — health, sports, performance, manufacturing, and education, among others. Speakers in this session gave specific examples in hardware, pediatric health, and opera.

Anthony connected this third pillar of MIT.nano to the fab and characterization facilities, highlighting how the Immersion Lab supports work conducted in other parts of the building. The Immersion Lab’s strength, he said, is taking novel work being developed inside MIT.nano and bringing it up to the human scale to think about applications and uses.

Artworks that are scientifically inspired

The Nano Summit closed with a reception at MIT.nano where guests could explore the facility and gaze through the cleanroom windows, where users were actively conducting research. Attendees were encouraged to visit an exhibition on MIT.nano’s first- and second-floor galleries featuring work by students from the MIT Program in Art, Culture, and Technology (ACT) who were invited to utilize MIT.nano’s tool sets and environments as inspiration for art.

In his closing remarks, Bulović reflected on the community of people who keep MIT.nano running and who are using the tools to advance their research. “Today we are celebrating the facility and all the work that has been done over the last five years to bring it to where it is today. It is there to function not just as a space, but as an essential part of MIT’s mission in research, innovation, and education. I hope that all of us here today take away a deep appreciation and admiration for those who are leading the journey into the nano age.”

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techblogger-things-blog · 6 years

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What is the Best Strategy to Prepare EDC for GATE Exam?

Hi guys today I’ll be sharing my strategy for how to prepare for Electronic Devices and Circuits for GATE . It’s one of the easiest subject from GATE point of view the only hard part is to memorize all the formulae from various topics apart from that it’s the least time consuming subject in respect to the weightage it shows in GATE exam preparation . EDC cousrse basically provides you with understanding of device physics which also forms a base for various circuit analysis and design courses.

In recent year level of question as well as the weightage of EDC in GATE exam has increased,from last 4 year anlaysis the minimum weightage seen for this subject was 6 and maximum was 12 in 2018 and 2017 it was one of the highest weighted subject and most of the toppers scored full marks in this subject .

Good knowledege of this subject can also help you after GATE in interviews of various IIT’s and PSU .If someone is looking forward to do specialization in Microelectronics this is one of the core subjects of this field ,where you will further learn in depth about device physics and after masters you can start your carrer as device engineer , a good device engineer are very higly paid.

GATE SYLLABUS

Here I have mentioned the GATE syllabus and i have divide it in parts and in next section i’ll pick out each part and discuss what to prepare and important topics for GATE

Semiconductor Physics:

Energy bands in intrinsic and extrinsic silicon, Carrier transport: diffusion current, drift current, mobility and resistivity, Generation and recombination of carriers ,Poisson and continuity equations.

Diodes

P-N junction, Zener diode.

Transistors

BJT, MOS capacitor, MOSFET .

Photovoltaic devices

LED, photo diode and solar cell .

Integrated circuit fabrication process:

oxidation, diffusion, ion implantation, photolithography and twin-tub CMOS process.

SYLLABUS DESCRIPTION AND PREPRATION STRATERGY

I would recommend you to give around 10 to 13 days for EDC in which you’ll have to cover theory, previous year GATE paper questions and solve some extra material for question practice . First of all, before starting this topic all of you should have basic idea about semiconductor, metals, and insulators, how are they classified, band model and bond model, direct and indirect band gap materials.

1). SEMICONDUCTOR PHYSICS (2-3 days)

This topic is some what between easy and moderate level ,but very important as it forms the basics for your further topics . Most of the parts are easy but few parts which are tricky and from which you can expect good level of questions are –

Enerdy band digram.

Carrier transport.

Graded impurity distribution.

Carrier generation and recombination.

This topic deals with semiconductor physics(particularly silicon) basically to study about properties of the semiconductor.

Silicon crystal structure ,no of valence electron ,Energy band gap etc. Graph related question can be sometime tricky so one should have good understanding of theory to answer those.

In intrinsic semiconductor study about its eletrical property like conductivity and it’s variation with temperature then mobility variation with temperature , velocity saturation at high electric field and understand graph of µ vs T and σ vs T Vd (drift velocity)vs E.

Then calculation position of intrinsic fermi level , calculation of electrons n and hole concentration p ,calculation of intrinsic concentration,mass action law ,charge neutrality, graph of ni vs T and ln(σ ) vs 1/T Once your’e done with intrinsic semiconductor Physic slightly modifies for extrinsic semicoductor calculation ,extra parts that you should know is compensated doping , non degenartive and degenerative semiconductor,variation in nature of semiconductor with temperature.

in carrier transport you should learn about drift and diffusion current density and their expression for n type and p type ,diffusion constant and mobility, life time of carrier, diffusion length ,Einstein relation.

Graded impurity distribution is very important topic in this you shoul learn about non uniform doping ,relation between doping profile and Electric field ,plot of electric field for different doping profile ,current density at equilibrium,good level numerical and graphical question can be framed from it.

Hall effect mechanism , hall coefficient for n type p type and intrinsic semiconductor,hall voltage and it’s application are important, formula based question can be asked from this.

Enerdy band digram is one of the most important and hard topic in EDC if you don’t understand it future topics can be really difficult for you as it forms the base for understanding other devices ,you should learn variation of energy band with applied voltage ,calculation of electric field from slope of band digram and fermi level variation for equilibrium case (also for non -equilibrium but not in detail).

In Carrier generation and recombination process you should learn about phonon(thermal) geneneration and photo(light) generation, expression for excess charge carrier due to light excitation and net recombination rate at steady state.

Poisson and continuity equation is same as in EMT you should learn about Minority carrier continuity equation this equation helps you to sove various problem on steady state injenction in semiconductor due to different excitation.

After learning this topics you can easily analyze physics of any device .

2). Diodes (2 days)

In diode Band Digrams can be difficulty to understand and calculation of Diode parameter like depletion width ,junction potential.

As a pre requisite you should have a good understanding of electrostatic which you can cover from EMT.

In GATE most question are asked from Step graded pn junction so you should know how to plot charge density profile for step graded pn juction and to derive plot for Electric field from it and Potential plot from Electric field and your Energy band diagram is just an inversion of your potential plot.

Charge density →Electric field →Potential plot →Energy band diagram

you should should be very clear about how to draw plot for all these not only for step graded but for any profile and to derive the above parameter.

In last few years many questions are asked from Juction law in diode and flow of charge carrier through drift and diffusion which can confuse you

Diode capcitance in reverse and forward bais for abrupt and linear junction are also important and break down mechanism in diode and there relation with doping concentration and temperature.

Transient in diode can be a hard part some time syou can expect good question from diode switching.

You should also give some time to schottky diode ,One sided pn junction and understand metal semiconductor junction this helps you to study MOS capcacitor

3).Transistor ( 3 days )

BJT (half day)

This is very small and easy topic in EDC as most of the theory you cover in Anlaog circuits some extra things that you might find difficult can be Band digrams in equilibrium and diiferent baising region.

You should study Early effect and it effect on various parameter and punch through then you should cover breakdown in BJT in different junction and relation between breakdown Vceo and Vcbo.

You should also cover topic like minority carrier distribution in different operating region , BJT time delay factor and its cut off frequency, Ebers Moll model.

MOS CAPACITOR(2 days)

This is one of the most important topic in EDC it’s basically like studying OPAM in Analog ckt. This topics will require time to understand and many tricky questionss can be asked from this topic . Most of the students finds it very difficult to learn. First you should start with basic working of MOS capacitor in all three regime accumulation , depletion, and inversion and then you should study it’s band diagram in all the three region then you should start with C-V curve of MOS in this you should know the concept of surface potential , flat band voltage and threshold voltage. For studying flatband voltage Vfb you should understand the concept of workfunction for metal and semiconductor then you should study about trapped oxide charges and finally the complete expression for Vfb in term of bothFor threshold voltage Vt you should study the expression for depletion charge , surface potential at Vt. Depletion width in the semiconductor is calculated by doing one sided pn juction calculation. You should also study the calculation of inversion layer charge density. Then you should learn expression for capacitance in a different region (Cox , Cdep and Cinv) and in the inversion region, you should analyze both LFCV and HFCV curve. Finally you should study fixed oxide and interface traps charge and their effect on the C-V curve.

MOSFET (half day )

Again most of the MOSFET theory you cover in analog but prior to MOSFET, you study MOS capacitor which forms the base for MOSFET .

You should study various short channel effect in MOSFET which cause variation in its parameter and you should study variation in threshold voltage with variation in a parameter like length , oxide thickness , substrate doping etc.

You should study all the operating region of MOSFET and solve a problem related to finding operation region of different MOSFET in ckt and graph as well the expression of gm with respect to Vgs , Id .

4) PHOTOVOLTAIC DEVICES (1 DAY)

LED

very easy and can be covered in no time, you should study about direct bandgap semiconductor and reaction between Eg and λ relation between material bandgap and cut in voltage and parameter like extraction efficiency , internal radiative efficiency and external efficiency.

PHOTODIODE

In this you should learn about it’s working , operation region and parameter like photo current, dark current, Respositivity and expression for sensitivity and quantum effiency

SOLAR CELL

It’s is the most important photovoltaic device with respect to GATE and can be some times hard for some students to learn , you learn it’s working and it’s I-V graph basically there are 4 parameter you should know Voc, Isc, Conversion efficiency and fill factor.

5)Integrated circuit fabrication process(half day)

these topics are very easy but most students don’t find proper material to study these topic .

oxidation – study about wet and dry oxidation basically how much temprature is required and quality of oxide produce

diffusion and ion implantation- both are used for the same purpose but study what is their specific application and temperature require to perform both and concept of annealing

photolithography – In this you should cover topic likemasking, Photoresist , etching.

twin-tub CMOS process – you should study all the steps required and in order for fabriaction.

This topic might come for one marks you can refer any device book for these process.

BOOKS TO BE USED

1). SEMICONDUCTOR PHYSICS and DEVICES 4e – DONALD A NEAMEN

DHRUBES BISWAS

This book is one of the best book for EDC it’s little hard to understand but once you’ll study this completely I can assure you that you won’t be losing any marks in EDC it cover every topic except fabrication process,many of it’s excersice question are directly given in GATE exam one should definetly refer this book for good understanding of EDC . DIODE, TRANSISTOR, PHOTOVOLTAIC DEVICES can be directly referred from this book GATE related every aspect is covered.

2). SOLID STATE ELECTRONIC DEVICES – BEN G STREETMAN

This book is also a really good book some what easier to understand and cover most of the syllabus for EDC in the gate.

REFERENCE MATERIAL: for refrence, you can use nptel , PDF are availabel for devices courses with really good content

#gate exam #preparation #competitive exam

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irispublishersengineeringscience · 3 years

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Iris Publishers - Global Journal of Engineering Sciences (GJES)

DFT study of the Optoelectronic properties of Sn1- xAxS (A= Au and Ag) Solar Cell Applications

Authored by Zeesham Abbas

Abstract

Doping effect of transition metal (TM) atoms on the photovoltaic features of Sn1-xAxS (A= Au and Ag) is investigated theoretically. DFT based calculations are used to explore electronic and optical properties by using full potential linearized augmented plane wave (FP-LAPW) method. Furthermore, generalized gradient (GGA) approximation is applied for the treatment of exchange and correlation potential. Ground state properties of these compounds are calculated by using GGA approximation. Our investigation shows that these compounds are metallic in nature. Origin of atomic/orbital electronic states in the energy band dispersion are explored in detail for S, Sn, Au and Ag from the calculated spectra of density of states. Optical parameters like complex dielectric function are also evaluated by using the information of energy band dispersions along with other associated optical properties like refractive index, optical conductivity, extinction coefficient, absorption coefficient, energy loss function and reflectivity coefficient. This study confirms that these TM based compounds can be used as promising compounds for technological optoelectronic applications having desired properties.

Introduction

In recent years, researchers have developed their interests in intermediate band (IB) materials due to their technological application is solar cells [1]. In next generation solar cells, the problem of efficiency can be overcome by developing IB photovoltaic materials. The working demonstration of intermediate solar cells

Arrows in the diagram show the possible electronic transitions. These electronic transitions can also take place in traditional way from valance band (VB) to conduction band (CB). In above figure, energy gaps between IB-CB, VB-IB and VB-CB are represented by Eg3, Eg2 and Eg1, respectively, and Fermi level is specified by EF. It can also be noted that IB can offer accommodation for the electrons travelling from VB to CB with less energy as compared to Eg1. Electrons can move from VB to IB and then from IB to CB in the materi als possessing IB. Several features of solar cells based on IB materials are presented in Figure 1. Existence of an isolated IB at Fermi level is the most prominent among all feature. Thermal relaxations can be produced due to interaction of electrons and the phonons of crystal lattice if this condition is not satisfied [2]. Moreover, IB must have a specified thickness so that the phenomenon of non-radiative recombination be avoided as much as possible. Electrons coming from VB with lower energies as compared to the energy difference between VB and CB can stay in IB only if it is partially filled.

Solar cells with this construction have higher conversion efficiencies then those established by Shockley limit [3], as reported earlier by Luque and Marti [1]. They reported the increase in the efficiency of these solar cells by operation and thermodynamic arguments. Diluted oxides with II-VI composition [4] or quantum dots can be introduced in the geometry [5] to prepare materials having IB.

Main focus of this investigation is the study of optical and electronic properties of Sn1-xAxS (A= Au and Ag) having IB with the help of quantum mechanical methodology. Additionally, electronic and optical properties of aforesaid compounds can also be calculated by using this methodology. We will discuss methodology and then investigated results will be discussed in the successive parts.

Methodology

Kohn-Sham equations are solved in order to calculate ground state properties of Sn1-xAxS (A= Au and Ag) by using self-consistent approach with the help of full potential linearized augmented plane wave (FP-LAPW) method [6] within the framework of DFT [7,8] as executed in WIEN2K code [9,10]. Exchange and correlation energy (Exc) were treated by using GGA approximation while calculating optical and electronic properties of Sn1-xAxS (A= Au and Ag). Optimized geometric structure was achieved through minimization of forces from the atoms of unit cell to carry out this DFT study. Kohn-Sham equations are solved in order to calculate ground state properties of Sn1-xAxS (A= Au and Ag) by using self-consistent approach with the help of full potential linearized augmented plane wave (FP-LAPW) method [6] within the framework of DFT [7,8] as executed in WIEN2K code [9,10]. Exchange and correlation energy (Exc) were treated by using GGA approximation while calculating optical and electronic properties of Sn1-xAxS (A= Au and Ag). Optimized geometric structure was achieved through minimization of forces from the atoms of unit cell to carry out this DFT study.

Muffin-tin spheres and the interstitial region (IR) are the two main parts of the crystal unit cell while working with FP-LAPW method. Here, core and valance electrons are treated as two separate groups of the electrons. In this technique, muffin-tin (MT) model is used to drive crystal potential. Valance electrons and non-overlapping atomic spheres with radius RMT (smallest muffin-tin radius) are termed as IR and muffin-tin spheres. The product of Spherical harmonics (Ylm) and radial solution of Schrodinger wave equation (SWE) at fixed energy for single particle (Vlm) is used to specify potential in muffin-tin spheres.

Results and Discussion

Electronic properties

In this section, we have presented the electronic properties of Sn1-xAxS (A= Au, Ag) namely the energy band structures and the density of states. Energy band structures are presented along highly symmetric points of Brillouin zone for a continuous energy range of -5.0 to 5.0 eV. Density of states are presented for a continuous energy range of -6.0 to 6.0 eV to determine the possible electronic transitions from CB to VB.

Band structure

In this section, energy band structures for the supercells of Sn1- xAxS (A= Au, Ag) are discussed along highly symmetric points of the irreducible Brillouin zone (IBZ). Calculated structures are shown in Figure 3 by setting Fermi level at 0 eV. An entirely isolated extra band can be seen at Fermi level of both the band structures of Sn1- xAxS (A= Au, Ag) known as intermediate band (IB). We can see that this band cross Fermi level. Intermediate bands can be divided into three types depending on the number of electrons in the IB as type I, type II and type III as shown in Figure 4. Type I and III are completely empty and they can be used to store electronic charge in the form of holes and electrons [12]. In literature, we can find several materials that carry IB for Li-ion batteries such as LiMn2O4, LiCoO2 etc [13]. 1-xAxS (A= Au, Ag) are potential candidates for technological applications in solar cells due to their partially filled IB. Materials with type-II IB are the main focus of this study. We can observe that energy band gap is present between IB and CB. This band gap decreases as we use Au as dopant instead of Ag. Energy band gap between IB and CB is approximately 1.0 and 1.5 eV for 1-xAxS and Sn1-xAgxS, respectively.

From the spectra of PDOS, we can note that VB can be divided into three parts as part A (-6.0 to -4.0 eV), part B (-4.0 to -2.0 eV) and part C (-2.0 to 0 eV). In part A, possible electronic transitions occur only due Sn[5s2] orbitals because all other orbitals are silent in this region. In part B, major electronic contributions come from Sn[5p2], Au[5d10] and S[3p4]. Finally, in part C of the VB, major electronic contributions come from Sn[5p2], Sn[5s2], Au[5d10] and S[3p4]. From the spectra of PDOS, we can note that S[3p4] and Sn[5p2] orbitals have key impact in CB, however, minor impact of Au[6S1] is also present.

We can observe from Figure 6 that Ag-atoms have key impact in the central part of valance band of Sn1-xAuxS, however, minor impact of S and Sn-atoms is also present. An IB due to hybridization of Ag-d and S-p orbital is also present around Fermi level. In conduction band, we can observe that S and Sn-atoms have key impact, however, minor impact of Ag-atoms is also present [12,13].

From the spectra of PDOS, we can note that VB can be divided into three parts as part A (-6.0 to -4.0 eV), part B (-4.0 to -2.0 eV) and part C (-2.0 to 0 eV). In part A, possible electronic transitions occur only due Sn[5s2] orbitals because all other orbitals are silent in this region. In part B, major electronic contributions come from Sn[5p2], Ag[4d10] and S[3p4]. Finally, in part C of the VB, major electronic contributions come from Sn[5p2], Sn[5s2], Ag[4d10] and S[3p4 ]. From the spectra of PDOS, we can note that S[3p4] and Sn[5p2] orbitals have key impact in CB, however, minor impact of Ag[5S1] is also present.

Fermi surface

Due to metallic nature of Sn1-xAxS (A= Au, Ag), Fermi surfaces (FS) are also investigated for the accessible electronic states of these compounds. Configuration of near Fermi bands present in Sn1-xAxS (A= Au, Ag) are shown in Figure 7 for the highly symmetric points of IBZ. Electrons near Fermi level play an important role in the electronic conductivity of the material. Understanding of the electronic properties of metallic compounds (band structure and DOS) can be obtained from their FS. Comprehensive knowledge of the electronic states (at Fermi level (EF)) can be obtained from FS. Electronic sheets and holes in the FS are represented by colored region and the empty spaces, respectively. Maximum region of the FS is empty for both compounds which show that these compounds are p-type semiconductors. From band structure, we can note that there is only one band that cross EF in both compounds. Thermoelectric properties such as electrical conductivity is directly related to the topography of the FS. Electrons with various velocities are represented by different colors in the FS.

Loss of rapidly moving electrons in the material can be explained by an important optical parameter known as energy loss function L(ω). Plasma oscillations are responsible for the characteristic behavior of the peaks present in the spectra of L(ω) and the frequencies associated with these oscillations are known as plasma frequencies. Plasmon excitations are responsible for the major peaks in the calculated spectra of L(ω). It is due to the mutual oscillations of the background atomic cores against the valance electrons in the longitudinal fashion with plasma frequency ωp. We can note from the spectra of L(ω) that there is negligible loss of electron energy up to 10.0 eV and then the spectra of L(ω) becomes maximum in upper UV region [17-20].

Optical conductivity σ(ω) and absorption coefficient α(ω) calculated for Sn1-xAxS (A= Au, Ag) are shown in Figure 9(c) and 9(d), respectively, over an entire energy range of 0 to 14 eV. Measure of the produced charge carriers due to breaking of the bond of atoms in the material due to incident photons which gives reasonable forward current is presented by σ(ω). Highest peaks of σ(ω) are present between 2.0 to 8.0 eV. We can note from the variations of σ(ω) show similar behavior as that of α(ω), k(ω) and ε2 (ω). Absorption of incident photons by the host materials is responsible for this behavior of σ(ω).

Both materials show no absorption of incident photons till 1.5 eV, inside the outlawed energy band. Because of electronic transitions from VB to CB, we can note prominent peaks in the spectra of α(ω) between 5.0 to 11.0 eV.

Conclusion

GGA potential scheme is used with DFT based FP-LAPW approach to explore the effect of TM atoms on ground state properties of Sn1-xAxS (A= Au, Ag). Electronic properties show that these compounds are metallic in nature. GGA functional is employed to calculate band structures and DOS (total and partial) in order to get accurate knowledge of the electronic properties. Our calculations show that these compounds possess intermediate band and energy band gap (between IB and CB) of these materials decreases as we change dopant from Ag to Au. We conclude that these materials are p-type semiconductors above IB. Optical parameters for Sn1-xAxS (A= Au, Ag) are also calculated to get insights of the usability of these compounds in technological optical applications. We conclude that these materials are not good reflectors as they reflect maximum of 50 % of the incident photons in upper UV region.

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