Multiple exciton generation (MEG) is a process in which the energy of an absorbed photon can be used to create two or more electron-hole pairs in the semiconductor. It also plays an essential role in developing new solar cells and high-performance optoelectronic devices. One of the major energy losses in photon-energy conversion is that if the photon has more energy than is needed to create the electron-hole pair, the excess energy is lost as heat. How to utilize the excess energy to improve photo-conversion efficiency and achieve MEG is necessary and challenging.
Dr Li MingJie of the Department of Applied Physics, one of the member of Photonics Research Institute (PRI), has led an interdisciplinary team recently developed high-quality halide perovskite nanocrystals with enhanced MEG. Nanocrystals (also known as quantum dots) developed by rational design can convert a high-energy photon into multiple electron-hole pairs, breaking the power conversion efficiency limit. The team successfully demonstrated that the internal quantum efficiency exceeded 100% at a low threshold by using such perovskite nanocrystals for the first time. The findings have been published in the highly influential journal Nature Photonics. Dr Li’s research has deepened the MEG mechanism’s understanding and provided valuable solutions for developing highly efficient light-harvesting techniques, including photovoltaics, photon detection, and solar-fuel production.
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