IRVINE, Calif., October 31, 2024 — Researchers at the University of California, Irvine are creating ultra-thin silicon solar cells that will help spread energy conversion technology by creating new ways for light and matter to interact. made possible. It can be used in a wide range of applications including thermoelectric clothing, vehicle and device charging.
This development is the subject of a paper recently published as a cover story in the journal ACS Nano, in which researchers at the University of California, Irvine are able to convert pure silicon from an indirect bandgap semiconductor to a direct bandgap semiconductor via a method that interacts with light. It depends on converting it into a gap semiconductor.
A team from the University of California, Irvine, in collaboration with scientists from Russia’s Kazan Federal University and Tel Aviv University, explored an innovative approach that modulates light rather than changing the material itself. They trapped photons in sub-3 nanometer asperities near bulk semiconductors, giving light new properties (magnification of momentum) and opening new interaction paths between light and matter. Researchers say that by “decorating” the silicon surface, they significantly improved the performance of the device and increased light absorption by an order of magnitude.
“In direct bandgap semiconductor materials, electrons transition from the valence band to the conduction band. This process requires only a change in energy; it is an efficient transition,” said first author and University of California, Irvine, Ph.D. said Dmitry Fishman, adjunct professor of chemistry at . “In indirect bandgap materials like silicon, an additional component, a phonon, is required to provide the electrons with the necessary momentum for the transition to occur. Photons, phonons, and electrons interact at the same place and time. This is unlikely, which is why the optical properties of silicon are inherently weak.
He notes that silicon’s poor optical properties as an indirect bandgap semiconductor are limiting the development of solar energy conversion and optoelectronics in general, but that silicon is the second most abundant element in the Earth’s crust and that the world’s He said that this is a drawback considering that it is the basis of . The computer and electronics industry was established.
“Photons carry energy, but very little momentum. But if we modify this textbook explanation and somehow give momentum to photons, we can excite electrons without the need for additional particles.” “We can do that,” said co-author Eric Potoma, a professor of chemistry at the University of California, Irvine. “This reduces the interaction to two particles, a photon and an electron, similar to what happens in direct bandgap semiconductors, increasing the absorption of light by a factor of 10,000, allowing light to be absorbed without changing the chemistry of the material itself. and the interaction of matter completely changes.”
Co-author Ara Apkarian, professor emeritus of chemistry at the University of California, Irvine, said: “This phenomenon fundamentally changes the way light and matter interact. Traditionally, textbooks teach about so-called vertical optical transitions, where a material absorbs light and a photon changes only the energy state of an electron. However, a photon with increased momentum can change both the energy and momentum states of an electron, metaphorically speaking, unlocking new transition paths that were previously unthinkable. , these photons enable oblique transitions and thus can “tilt the textbook.” This has a dramatic effect on the material’s ability to absorb or emit light. ”
According to the researchers, this development creates an opportunity to take advantage of recent advances in semiconductor manufacturing technology at scales below 1.5 nanometers, which could have implications for light sensing and light energy conversion technologies.
“With the growing impacts of climate change, the transition from fossil fuels to renewable energy is more urgent than ever. Solar energy is key to this transition, but the Commercially available solar cells are not sufficient,” Potoma said. “Silicon has a low ability to absorb light, so these cells require thick layers (approximately 200 micrometers of pure crystalline material) to effectively capture sunlight. This reduces manufacturing costs. In addition to increasing the recombination of charge carriers, it also limits efficiency. Thin-film solar cells, which our research brings one step closer to reality, are widely recognized as a solution to these challenges.”
Other co-authors on the study include Jovany Merham and Aleksey Noskov of the University of California, Irvine. Kazan Federal University researchers Elina Battalova and Sergei Harintsev. Tel Aviv University researchers Liat Katlivas and Alexander Kotriyar. This project received funding from the Chan Zuckerberg Initiative.
About the University of California, Irvine’s Brilliant Future Campaign: Launched to the public on October 4, 2019, the Brilliant Future campaign aims to increase awareness and support for the university. By engaging 75,000 alumni and attracting $2 billion in philanthropic investment, UC Irvine aims to reach new heights of excellence in student success, health and wellness, research, and more. The Faculty of Physical Sciences will play a key role in the success of the campaign. For more information, visit https://brilliantfuture.uci.edu/uci-school-of-physical-sciences.
About the University of California, Irvine: Founded in 1965, the University of California, Irvine is a member of the prestigious Association of American Universities and is ranked among the nation’s top 10 public universities by U.S. News & World Report. The campus has produced five Nobel Prize winners and is known for its academic achievements, top-notch research, innovation and anteater mascot. Led by President Howard Gilman, the University of California, Irvine has more than 36,000 students and offers 224 degree programs. Located in one of the safest and most economically vibrant areas in the world, we are Orange County’s second largest employer, contributing $7 billion annually to the local economy and $8 billion to the state as a whole. There is. For more information about the University of California, Irvine, visit www.uci.edu.
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