Mixed Ionic‐Electronic Conduction Enables Halide‐Perovskite Electroluminescent Photodetector

Abstract Light emission and detection are the two fundamental features of optoelectronic communication systems. Until now, both functions have been realized with a p–n diode, which is used in a wide range of applications. However, due to the competing dynamics of carrier injection and photocarrier collection, in such devices, electroluminescence and photodetection are realized separately by switching the direction of the applied electrical bias. Here, mobile ions in halide perovskites are benefited from to demonstrate electroluminescence and photodetection simultaneously, without switching the direction of the applied electrical bias. The electroluminescent photodetector consists of a CsPbBr 3 microwire integrated with electrodes made of a single‐walled carbon nanotube thin film, providing Schottky barriers at the interfaces. The dual functionality stems from the modulation of these barriers by mobile ions in cooperation with photogenerated charge carriers. Furthermore, such complex charge dynamics additionally result in a novel effect: light‐enhanced electroluminescence. The new optoelectronic phenomena demonstrated in the simple lateral device design will expand the applications of mixed ionic‐electronic conductors toward cheap and efficient multifunctional optoelectronic devices able to simultaneously generate and receive optical data.