MPA-Mediated Control of HgTe Quantum Dot Dispersion in an HgI₂-Based System

s HgTe quantum dots (QDs) are promising for infrared optoelectronic applications due to their size-tunable bandgap and solution-processable nature. However, conventional synthesis methods often result in aggregation and instability, limiting their practical use. This study presents a strategy to improve the dispersibility of HgTe QDs by using mercuric iodide (HgI₂) as the mercury precursor and 3-mercaptopropionic acid (MPA) in combination with oleic acid as the ligands during the quenching stage. Comparative experiments showed that MPA-treated QDs exhibited improved dispersion, with a reduced hydrodynamic diameter (~135   nm) compared to those without MPA (~180   nm). Additionally, photoconductive devices fabricated with MPA-treated QDs demonstrated significantly better performance. These devices exhibited higher switching ratios and responsivity, reflecting the improved dispersion and surface stabilization of the QDs, which enhanced charge transport efficiency and reduced recombination losses. This work provides an effective approach for controlling dispersion and enhancing the performance of HgTe QDs for infrared optoelectronics.