Adjusting Microscale to Atomic‐Scale Structural Order in PbS Nanocrystal Superlattice for Enhanced Photodetector Performance
Chuanglei Wang, Zhenjun Chen, Zheng Liu, Tianchan Ma, Xiya Chen, Menglong Zhang, Dongxiang Luo, Byung‐Ryool Hyun, Xiao Liu
Abstract
Abstract An investigation is presented into the effect of the long‐range order on the optoelectronic properties of PbS quantum dot (QD) superlattices, which form mesocrystals, for potential use in photodetector applications. By self‐assembly of QD nanocrystals on an Si/SiO x substrate, a highly ordered and densely packed PbS QD superlattice with a microscale size is obtained. The results demonstrate that annealing treatment induces mesocrystalline superlattices with preferred growth orientation, achieved by dislodging ligands. The improved orientation and electronic coupling of the mesocrystalline superlattices exhibit superior photodetector performance compared to disordered QD structures and closely packed superlattices. This improved performance is attributed to atomic alignment between QDs, leading to enhanced electronic coupling. The findings suggest that these mesocrystalline superlattices have promising potential for the next generation of QD optoelectronic devices.