80 / 2023-04-13 09:29:08

Photoelectric effects of Metal Halide Perovskite and Applications for X-ray photocathode

photocathode; metal halide perovskite; X-ray detection

Photocathodes - materials that convert photons into electrons via the photoelectric effect - are a key basis for many modern technologies that rely on light detection or the production of electron beams. However, the photocathodes that exist today are based on traditional metals and semiconductors, most of which have been discovered over 60 years. Progress in this mature field is limited to the improvement of photocathode properties based on complex materials engineering. Therefor, it is very important to explore new and more efficient photocathode materials for the development of photocathode. Metal halide perovskite has attracted broad attention in optoelectronic devices fields since the first metal halide perovskite based solar cell during the last decade. In addition to their excellent performance in solar cells and light-emitting diodes, perovskites have made significant progress in the field of X-ray detection. Metal halide perovskites, such as CsPbI₃, CsPbBr₃, Cs₃Bi₂I₉, et al, contain high-Z atoms (such as Cs, Pb, and I) with a large capacity for x-ray absorption. Furthermore, perovskite thin film can be prepared via a facile solution method with high oxygen and moisture stability. Highly efficient photoelectric effect in cesium lead halide perovskites has been reported in the visible and violet light regions. In addition, the energy loss of electron transport in materials is an important factor affecting photoelectric efficiency. The energy loss of electrons in perovskites is mainly caused by electron–phonon collisions, while electron–electron collision is the dominated mechanism of electron energy loss in metals. The energy loss of electron–phonon collision is much smaller than electron–electron collision. Therefore, we expect metal halide perovskites to have efficient photoelectric effect and be suitable for X-ray photocathode. In this work, we prepared thin film samples of various metal halide perovskites and tested their photoelectric effects under X-ray. The test data show that the photoelectric efficiency of metallic halide perovskites is better than that of conventional gold photocathodes in the X-ray region. X-ray detectors based on metal halide perovskites have been applied in laser fusion experiments and achieved excellent performance.​