A Universal Microscopic Patterned Doping Method for Perovskite Enables Ultrafast, Self‐Powered, Ultrasmall Perovskite Photodiodes

Abstract Novel metal halide perovskite is proven to be a promising optoelectronic material. However, fabricating microscopic perovskite devices is still challenging because the perovskite is soluble with the photoresist, which conflicts with conventional microfabrication technology. The size of presently reported perovskite devices is about 50 µm. Limited by the large size of perovskite optoelectronic devices, they cannot be readily adopted in the fields of imaging, display, etc. Herein a universal microscopic patterned doping method is proposed, which can realize microscale perovskite devices. Rather than by the conventional doping method, in this study the local Fermi level of perovskite is modulated by the redistributing intrinsic ion defects via a polling voltage. A satisfactorily stable polarized ion distribution can be achieved by optimization of the perovskite material and polling voltage, resulting in ultrafast (40 µs), self‐powered microscale (2 µm) photodiodes. This work sheds light on a route to fabricate integrated perovskite optoelectronic chips.