Precursor engineering enhanced responsivity of lead sulfide quantum dots shortwave infrared photodiode

Abstract

Lead sulfide (PbS) quantum dots (QDs) exhibiting the narrow bandgap (Eg < 0.9 eV) provide a promising avenue to high performance, inexpensive shortwave infrared (SWIR) photodetector. However, most PbS-QD based SWIR photodiodes suffers from low responsivity and low external quantum efficiency (EQE) in the IR range due to insufficient ligand exchange. Here, we report a precursor engineering strategy that facilitates the commonly used Tetrabutylammonium iodide (TBAI) ligand exchange. We synthesized the PbS QDs from Lead Oxide (PbO) and lead acetate trihydrate (PbAc2·3H2O). Compared with PbS QDs photodiode based on PbO, the responsivity and EQE of PbS QDs photodiode based on PbAc2·3H2O have been improved from 0.15 to 0.586A/W and 12.35 to 47.27%.