Pyro-phototronic effect in colloidal quantum dots on silicon heterojunction for high-detectivity infrared photodetectors

Solution-processed colloidal quantum dots (CQDs) have attracted significant interest for infrared photodetection, particularly due to their easy integration with silicon-based electronics. Among these, silver sulfide (Ag₂S) CQDs stand out as non-toxic infrared semiconductors. However, their application in photodetectors has traditionally shown lower detectivity compared to devices based on lead sulfide and mercury telluride CQDs. Here we demonstrate report Ag₂S CQD/silicon p-n heterojunction photodetectors that exhibit substantially enhanced detectivity. This improvement was facilitated by the pyro-phototronic effect (PPE) in Ag₂S CQDs, which significantly increases the photocurrent. Consequently, the detectivity of the CQD/silicon photodetector was improved by a factor of 17, reaching 4.1×10¹⁰ Jones at 980 nm. These findings pave the way for new opportunities in utilizing CQDs for pyro-phototronic driven, solution-processed optoelectronic devices.