Lead sulfide quantum dot assembly with biocompatible mechanical property and tunable hydrophilicity

Abstract

The outstanding optical and electronic properties of lead sulfide (PbS) colloidal quantum dots have broad applications in nanotechnology. They are composed of an inorganic semiconductor core and organic ligands. Here, using 2,3-dimercaptosuccinic acid (DMSA) as a reactant, we synthesized PbS nanoparticles and assembled them on a pigeon feather substrate through a self-assembled monolayer process. This assembly process results in a significantly higher increase in the modulus and hardness of the synthesized PbS material compared to that of the PbS materials reported previously. Particularly, there is only a slight increase in the mechanical properties of the PbS layer compared with the bio-template, indicating the compatibility between the coating and base material, demonstrating its potential for biological applications, such as wearable flexible electronic devices. In addition, the DMSA of the rich carboxylic groups as a passivator promoted the tunability of the PbS surface from hydrophilic to superhydrophilic. The influence of the surface roughness of the PbS layer on the wetting behavior conforms to the Cassie–Baxter model.