Hydrogen-driven engineering of electronic properties in PbS quantum dots and superlattices

Abstract

Colloidal PbS quantum dots are promising materials for optoelectronic applications thanks to their tunable properties and ability to self-assemble into superlattices. Using first-principles density functional theory with van der Waals corrections, we investigate the impact of hydrogen surface functionalization on the structure, electronic properties, and self-assembly behavior of PbS quantum dots. We find that hydrogenation introduces shallow defect states near the band edges and stabilizes simple cubic superlattice structures, in contrast to the behavior of stoichiometric nanoparticles. The resulting assemblies exhibit a direct band gap with interband states, as well as the mechanical softness characteristic of van der Waals solids. These findings highlight hydrogen treatment as a simple yet effective strategy for tailoring interparticle interactions and electronic properties in PbS quantum dot superlattices, thereby enhancing their potential for photovoltaic and optoelectronic applications.