The Polymer Society of Korea

Abstract

Infrared colloidal quantum dots (CQDs) are promising materials for next-generation optoelectronics. Among them, indium arsenide (InAs) CQDs have drawn attention for their suitability in emerging applications such as wearable devices. However, achieving efficient surface passivation remains a critical challenge for high-performance InAs CQD-based infrared photodetectors. In this study, we combine a sequential ligand adsorption model based on density functional theory calculations, together with systematic experiments to investigate atomic-scale ligand adsorption on InAs CQDs. The results indicate that passivation efficiency is determined by steric hindrance from halide ion size and surface electrostatic interactions. Smaller halide ligands allow for denser surface coverage, leading to enhanced charge transport. As a result, an optimized InAs CQD photodiode exhibits a specific detectivity of 3.2×10¹² Jones at 980 nm.