Selective Surface Engineering of Perovskite Microwire Arrays

The surface of low‐dimensional perovskites play a crucial role in determining their intrinsic property. Understanding their characteristics and the influence of certain surfaces is valuable in designing functional surface‐engineered structures. Meanwhile, surface passivation can also be applied to stabilize and optimize the state‐of‐the‐art perovskite‐based optoelectronics. Herein, cesium lead bromide (CsPbBr3) microwire parallel arrays are designed and fabricated with specific (100)‐terminated crystal planes, which exhibit excellent photodetection performance with long‐term environment stability >3000 h. Notably, it is uncovered experimentally and theoretically that environmental oxygen can not only passivate the Br‐vacancy‐related trap states on the (100) surface, but also create charge carrier nanochannels to enhance the (opto)electronic properties. The coupling effects between oxygen species and the specific terminated crystal planes of perovskites highlight the importance of surface engineering for designing and optimizing perovskite‐based devices. Specific (100)‐terminated surfaces of perovskite microwire arrays are designed and obtained, which exhibit excellent photodetection performance with long‐term environment stability >3000 h. Moreover, the successful manipulation of oxygen passivation to the device is uncovered experimentally and theoretically.