SrTiO₃/CuNi‐Heterostructure‐Based Thermopile for Sensitive Human Radiation Detection and Noncontact Human–Machine Interaction

Abstract Noncontact interactive technology provides an intelligent solution to mitigate public health risks from cross‐infection in the era of COVID‐19. The utilization of human radiation as a stimulus source is conducive to the implementation of low‐power, robust noncontact human–machine interaction. However, the low radiation intensity emitted by humans puts forward a high demand for photodetection performance. Here, a SrTiO_3−x/CuNi‐heterostructure‐based thermopile is constructed, which features the combination of high thermoelectric performance and near‐unity long‐wave infrared absorption, to realize the self‐powered detection of human radiation. The response level of this thermopile to human radiation is orders of magnitude higher than those of low‐dimensional‐materials‐based photothermoelectric detectors and even commercial thermopiles. Furthermore, a touchless input device based on the thermopile array is developed, which can recognize hand gestures, numbers, and letters in real‐time. This work offers a reliable strategy to integrate the spontaneous human radiation into noncontact human–machine interaction systems.