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 10⁴, 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.