Long‐Lived Hole Storage Enabled Internal Photogating in a 2D Perovskite/MoSe ₂ Heterostructure for High‐Sensitivity Weak‐Light Imaging

ABSTRACT

Two‐dimensional Ruddlesden–Popper perovskites are promising for optoelectronics due to their environmental robustness. However, their performance is often limited by inefficient charge transport and interfacial recombination. Herein, a van der Waals heterojunction photodetector is constructed by integrating 2D PEA ₂ PbI ₄ perovskite with few‐layer MoSe ₂ , which demonstrates internal photogating enabled by long‐lived hole storage, leading to a synergy of ultrahigh sensitivity and fast response. Spectroscopic and ultrafast dynamical probes reveal an atomically sharp interface with a type‐I band alignment, facilitating picosecond electron transfer from the perovskite to MoSe ₂ while localizing holes within the perovskite lattice for hundreds of picoseconds. This mechanism manifests as a pronounced photogating effect in the device, efficiently modulating the conductivity of the MoSe ₂ channel. Consequently, the device achieves a high responsivity of 27 A/W, a specific detectivity surpassing 2 × 10 ¹³ Jones, and a sub‐millisecond response speed, all without increasing the dark‐current noise. Leveraging this exceptional weak‐light sensitivity, clear single‐pixel imaging is successfully demonstrated across a broad spectrum (405–808 nm) under an ultralow irradiance down to 56 nW/cm ² . This work elucidates a promising material platform and device paradigm for next‐generation high‐performance, low‐power photodetection and imaging systems.