Chinese scientists find new ways to improve the photoelectric conversion efficiency of solar cells

A research team from Jilin University in China has made new progress in revealing the photophysical mechanism of two-dimensional semiconductor materials, and found new ways to improve the photoelectric conversion efficiency of solar cells. The results were recently published in the internationally renowned academic journal 'Nature Communications'. In recent years, a two-dimensional semiconductor monolayer material that not only has a limit physical thickness similar to that of graphene, but also has a direct bandgap energy band structure that graphene lacks, a transition metal chalcogenide monolayer, has shown a better performance than graphite. Alkenes are also rich in photophysical properties, and have received extensive attention in the field of ultra-thin and flexible energy conversion and storage. The research team of Professor Sun Hongbo-Wang Haiyu from the State Key Joint Laboratory of Integrated Optoelectronics, School of Electronic Science and Engineering, Jilin University, in cooperation with the National University of Singapore, Imperial College London and other units, discovered that the molybdenum disulfide monolayer is a representative of this type of material. The new method of high-energy hot carrier generation and extraction efficiency provide a principle explanation for the in-depth understanding of the photophysical image and working mechanism of related two-dimensional devices. It also helps to improve the application of two-dimensional semiconductor materials in solar cells and other optoelectronic applications. Energy conversion efficiency provides new inspiration. It is understood that in photovoltaic applications represented by solar cells, photoelectric conversion efficiency is one of the most important indicators. In traditional photovoltaic devices made of bulk semiconductors, photo-generated heat carriers will relax extremely quickly to the bottom of the energy band by emitting phonons. This process will generate heat that cannot be effectively utilized. The above limits the maximum photoelectric conversion efficiency of solar cells to about 31%; if some characteristics of the material can be used to fully slow down the cooling process of hot carriers, these hot carriers can relax before the bottom of the energy band If extracted, it is theoretically possible to double the highest photoelectric conversion efficiency of photovoltaic devices.