Low‐Voltage Photodetectors with High Responsivity Based on Solution‐Processed Micrometer‐Scale All‐Inorganic Perovskite Nanoplatelets

All‐inorganic photodetectors based on scattered CsPbBr3 nanoplatelets with lateral dimension as large as 10 µm are fabricated, and the CsPbBr3 nanoplatelets are solution processed governed by a newly developed ion‐exchange soldering mechanism. Under illumination of a 442 nm laser, the photoresponsivity of photodetectors based on these scattered CsPbBr3 nanoplatelets is as high as 34 A W−1, which is the largest value reported from all‐inorganic perovskite photodetectors with an external driven voltage as small as 1.5 V. Moreover, the rise and fall times are 0.6 and 0.9 ms, respectively, which are comparable to most of the state‐of‐the‐art all‐inorganic perovskite‐based photodetectors. All the material synthesis and device characterization are conducted at room temperature in ambient air. This work demonstrates that the solution‐processed large CsPbBr3 nanoplatelets are attractive candidates to be applied in low‐voltage, low‐cost, ultra highly integrated optoelectronic devices. Solution‐processed scattered large CsPbBr3 nanoplatelets bridge across metal electrodes in a planar photodetector configuration. Due to the strong light absorption and excellent in‐plane charge carrier transport in all‐inorganic CsPbBr3 nanoplatelets, the photodetectors achieve high responsivity of 34 A W−1 driven by a low voltage of 1.5 V, demonstrating great potential for use in portable devices.