Shape- and Trap-Controlled Nanocrystals for Giant-Performance Improvement of All-Inorganic Perovskite Photodetectors

In the last few years, all-inorganic perovskite CsPbBr3 nanocrystals (NCs) have attracted tremendous attention for its high carrier mobility, long carrier diffusion length, excellent visible light absorption, and more importantly superior air stability. In fact, photodetectors (PDs) are designed and fabricated using the CsPbBr3 NCs with very high performance. Herein, by optimizing the NC shape, size, and surface passivation, the CsPbBr3 PDs are developed with an even higher performance. It is found that the PDs based on CsPbBr3 nanoribbons show the best photoresponse among all common NC structures synthesized. Moreover, it is found that 6,6-phenyl-C61-butyric acid ethyl ester can be used to passivate defects on the CsPbBr3 nanoribbon surface and shows the charge transfer. As a result, the device displays superior photoresponsivity (R = 18.4 A W-1), excellent signal-to-noise ratio, as high as 10(4), and a very sharp rise/decay time (8.7/3.5 ms). The method demonstrated may offer an attractive strategy to improve sensitivity for all-inorganic perovskite PDs in general.