Ligand Influence on CuInS2 Quantum Dot Photoconductive Films
Yizun Wang1, Hrilina Ghosh1, Siva Sivoththaman1
1Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Nanomaterials (Basel, Switzerland)
|February 26, 2026
Summary
Ligand choice significantly impacts copper indium disulphide quantum dot properties. Shorter ligands like MPA and TGA enhance charge transport, improving photodetection in simple devices.
Area of Science:
- Materials Science
- Nanotechnology
- Optoelectronics
Background:
- Copper indium disulphide (CuInS2) quantum dots (QDs) are promising nanomaterials.
- Ligand chemistry plays a crucial role in tuning QD properties.
Purpose of the Study:
- Investigate ligand effects on CuInS2 QD optical and electrical properties.
- Assess QD suitability for photodetection using simple device structures.
Main Methods:
- Synthesized CuInS2 QDs with dodecanethiol (DDT) ligands.
- Exchanged DDT with thioglycolic acid (TGA), mercaptopropionic acid (MPA), and thioacetamide (TAA).
- Fabricated metal-semiconductor-metal (MSM) devices and characterized optical and electrical performance.
Main Results:
- TAA ligands caused PL quenching due to surface defects.
- MPA- and TGA-capped QDs showed 7-9x higher currents than DDT-capped QDs.
- Enhanced photocurrent-to-dark current ratios (2.6 for MPA, 1.7 for TGA) were observed.
- TGA-capped QD devices responded well to pulsed UV light.
Conclusions:
- Shorter ligands (MPA, TGA) improve charge transport in CuInS2 QD films.
- CuInS2 QDs with optimized ligands show potential for photodetection and optical switching.
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