Self-powered all-quantum dot based broadband photodetectors for color imaging and heart rate monitoring

Abstract

Self-powered broadband photodetectors (PDs) are crucial in various daily applications. However, traditional Si-based broadband PDs have limited responses in the infrared and ultraviolet spectra, hindering further development. To address this challenge, this work proposes self-powered all-quantum dot (QD) based broadband PDs. These PDs are integrated with SnO₂ QDs/PbS-I QDs/PbS-EDT QDs, enabling broadband photodetection from 300 to 1000 nm. By adjusting the thickness of the SnO₂ QD layer, these PDs exhibit high self-powered responsivity (401.8 mA W⁻¹), high detectivity (4.8 × 10¹² Jones), high EQE (62%), fast response speed (rise time 11.4 μs; decay time 14.7 ms) and ultrahigh on/off ratio (1.4 × 10⁴). These PDs can be used for long-distance color recognition imaging and human heartbeat monitoring. This study demonstrates the potential application of all-quantum dot PDs in the field of broadband photodetection.