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

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

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

Details

Original languageEnglish
Article number2201897
Number of pages10
JournalAdvanced optical materials
Volume11
Issue number1
Publication statusPublished - 4 Jan 2023
Peer-reviewedYes

External IDs

WOS 000877857400001

Keywords

Keywords

  • defects, high linear dynamic range, intensity-dependent photocurrent dynamics, low dark current, PbS quantum dots, photodetectors, Intensity-dependent photocurrent dynamics, High linear dynamic range, Photodetectors, Low dark current, Defects