Light‐State Rectification Behaviors Induced by Interlayer Excitons in Mixed‐Dimensional Single‐Crystalline Perovskite Heterostructures

Abstract Stacking different layers into van der Waals heterostructures (vdWHs) provides an attractive approach to integrating intrinsic prominent properties of the constituents. Mixed‐dimensional vdWHs that can interact with external fields are particularly intriguing because they host interlayer excitons (IXs) and thereby exhibiting rich physical phenomena and novel device behaviors. However, previous studies of IXs have primarily focused on TMDs systems, leaving the excitonic phenomena and correlated physics in perovskite heterostructures poorly understood. Here, the 2D‐3D ((BA) 2 PbBr 4 ‐CsPbBr 3 ) single‐crystalline perovskite vdWHs are designed to discover the modulation effects of IX states on the optical and optoelectronic properties. Interestingly, the vdWHs exhibit a newly emerging IXs emission at 546 nm and an obvious broadening phenomenon in FWHM. The vdWHs‐based photodetectors display novel light‐state rectification behaviors that can change the output photocurrents from fully off states to rectified states after illumination, resulting in a high rectification ratio up to 24342 and an obvious enhanced on/off ratio of 7000. The attractive results are attributed to the presence of IX states, which facilitate carrier hopping at the interfaces. This work establishes mixed‐dimensional single‐crystalline perovskite heterolayers as a highly adaptable platform for exciton research and applications.