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

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.