Bioinspired Dual-Mode Nanowire Photodetector with High Responsivity for Wide Dynamic Range Image Sensing

Machine vision systems require image sensors possessing a wide dynamic range (DR) and superior responsivity to adapt to vastly varying illumination conditions. While conventional silicon-based image sensors are inherently limited in DR - often necessitating complex auxiliary circuitry or computational correction, they still fail to capture the full details of natural scenes. Inspired by the complementary functions of rod and cone cells in the human retina, a dual-mode photodetector based on Cd(S, Se) nanowire with S-vacancy-induced trap states is developed. This device exhibits spontaneously switchable transient and persistent photoconductivity behaviors, which simulate the photopic and scotopic vision of the human retina, respectively. This biomimetic device achieves a remarkable responsivity of 3.23 × 10⁷ A W⁻¹, an ultra-low threshold of 2 × 10⁻¹² W cm² for light detection, and an ultra-wide DR of 193 dB at 638 nm. When integrated into an imaging system, it enables high-resolution reflective imaging under ambient light and high-contrast imaging at ultra-low illumination, which can effectively improve image recognition accuracy. This adaptive photodetection strategy represents a promising avenue for enhancing machine vision performance across dynamic lighting conditions.