Highly Sensitive Visible–LWIR Ultrabroadband Photodetector via Electron–Phonon Synergy for Noncontact Human–Machine Interaction

ABSTRACT Ultrabroadband photodetectors based on photothermoelectric (PTE) materials hold great promise for enabling ubiquitous perception and intelligent automation in modern society. However, the simultaneous engineering of electrical and thermal transport in PTE materials remains a major challenge toward maximizing device performance. Here, we introduce an interstitial‐hydrogen doping strategy that enables the coordinated optimization of electron and phonon transport in SrTiO 3 . Specifically, the enhanced mobility (7.4 cm 2 ·V − 1 ·s − 1 ) arises from the reduced electron effective mass, whereas the suppressed thermal conductivity (9.95 W·m − 1 ·K − 1 ) originates from the lattice‐level local structural perturbations. Furthermore, an interstitial‐hydrogen‐engineered SrTiO 3 (HSTO) PTE photodetector array is realized for high‐sensitivity ultrabroadband detection. Across the spectral range from 532 nm to 8.47 µm, the device delivers a self‐powered responsivity exceeding 3 V/W, alongside with a response time of 87.9 ms. Moreover, shrinking the device dimensions and introducing a suspended structure can further boost the overall performance. With the assistance of machine‐learning algorithms, it enables fully automatic hand‐gesture recognition with an accuracy of 100%. This work provides a new approach to enhancing PTE conversion efficiency toward ultrabroadband photodetection and opens new avenues for noncontact intelligent human–machine interfaces.