Ionic‐Electronic Coupled 2D Semiconductor with Giant TCR for Broadband Visible‐to‐Infrared Dual‐Mode Photodetection

Abstract 2D ionic‐electronic coupled materials, offering mobile ions as an additional degree of freedom, open new avenues for device functionality beyond traditional electronic systems. However, harnessing ionic‐electronic interactions to achieve broadband photodetection remains unexplored. Here, a van der Waals ionic‐electronic semiconductor is reported that exhibits an ultrahigh and anisotropic temperature coefficient of resistance (TCR) of −7.29% °C −1 , which is attributed to its high ionic activation energy. Leveraging both photoelectric and bolometric effects, AIPSe enables dual‐mode photodetection across the visible to near‐infrared range. Through device engineering with asymmetric Schottky contacts and ionic migration modulation, photodiodes with an ultrahigh rectification ratio of ≈108 and bias‐tunable dual‐mode operation: photovoltaic detection with a responsivity of 0.385 A W −1 at 532 nm, and bolometric sensing with 0.486 A W −1 at 1550 nm is achieved. These devices demonstrate spectral self‐recognition, secure dual‐band optical communication, and multi‐wavelength imaging capabilities. The work establishes ionic‐electronic correlated transport in 2D materials as a new paradigm for beyond‐bandgap optoelectronic technologies.