Solution-processed self-powered near-infrared photodetectors of toxic heavy metal-free AgAuSe colloidal quantum dots

Abstract

Self-powered, high detectivity, solution-processed near-infrared (NIR) quantum dot photodetectors based on novel alloyed AgAuSe quantum dots (QDs) are fabricated for the first time and their photoelectric properties are explored. AgAuSe QDs were capped with 1,2-ethanedithiol by ligand exchange to improve the carrier transfer of the film. Their thin films were successfully deposited on the substrate of the interdigital Au electrodes with Schottky contacts. There is an inevitable subtle distinction between the contact with the two ends of the electrodes, leading to the self-powered performance of the devices. The devices exhibit a high specific detectivity of 1.55 × 10¹⁰ Jones (>10⁹ Jones) under weak illumination at zero bias voltage and room temperature. They are promising in a wide range of applications, such as in low cost and large area smart sensors, the Internet of Things (IoT), imaging devices, wearable devices and many other emerging fields.