2D CuInP₂Se₆ in High‐Sensitivity UV‐vis And X‐Ray Detection

Abstract Metal thio(seleno)phosphates are renowned for their multifaceted physical characteristics and versatile applications, particularly in optoelectronics. In detection applications, a low and stable dark current is crucial, enhancing the sensitivity and signal‐to‐noise ratio of detectors. Herein, a van der Waals layered material has synthesized, CuInP₂Se₆. Despite its nanometric scale, 2D CuInP₂Se₆ detector transcends the conventional absorption inefficiencies tied to ultrathin materials. It delivers exceptional ultraviolet–visible detection, characterized by an ultralow, stable dark current of 150 fA, and a noise power density of 27.7 fA Hz^−1/2 at room temperature. The in‐depth investigation reveals a responsivity of 4.47 A W⁻¹, an external quantum efficiency of 1369%, a special detectivity of 1.44 × 10¹³ Jones, and a rapid response speed of 280 µs, positioning it at the pinnacle of 2D photodetector performance. The CuInP₂Se₆’s ultralow, stable dark current paves the way for X‐ray detection, achieving an unprecedented sensitivity of 1.32 × 10⁵ µC Gy_air⁻¹ cm⁻² and a low detection limit of 0.15 µGy_air s⁻¹. Furthermore, 2D CuInP₂Se₆ detector exhibits a remarkable image‐sensing capability, adeptly capturing intricate patterns with high resolution. This discovery indicates its promise in revolutionizing integrated micro/nano optoelectronic devices, opening avenues for advancements in light and X‐ray detection and imaging technologies.