Impact of Ligands on the Performance of PbS Quantum Dot Visible–Near‐Infrared Photodetectors

Solution-processed lead sulfide quantum dots (PbS QDs) are an excellent candidate for photodetector applications because they exhibit broadband absorption, a wide range of tuneable bandgaps, high stability in air, and mechanical flexibility. However, crucial criterion the fabrication high-performance photodetectors is selection ligands, which can facilitate charge carrier transport between PbS QDs passivate surface defects. In this work, authors have studied effect traps on performance QD that fabricated using different types intensity-dependent photoresponse dynamics. The best devices with halide ligands show dark current density 5 × 10−9 A cm−2 at −0.2 V, one lowest values reported thus far solution-processed QD-based photodetectors. Moreover, these linear dynamic (≈90 dB) detectivity (>1013 Jones), addition to f-3 dB greater than 100 kHz without application external voltage bias wavelength 784 nm. These results suggest appropriate lower better device be fabricated.