One pot synthesis of PbS/Cu$_{2}$S core-shell nanoparticles and their optical properties

Abstract

The synthesis of PbS/Cu$_{2}$S core-shell nanoparticles with emission on the visible range and with improved luminescence properties was carried out by the colloidal solution-phase growth method by using simple stabilizers such as trisodium citrate and 3-mercaptopropionic acid. The core shell arrangement for particles with different crystalline structure was achieved, in addition this is the first report related to the synthesis PbS/Cu$_{2}$S core-shell system. The data obtained from absorption spectra, PL spectra, and HRTEM image provided direct proof of the formation of PbS core with size around 11 nm and Cu$_{2}$S shell of 5 nm thickness. According to the UV-vis absorption and PL spectrum, the optical characteristics observed in the synthesized material correspond to a PbS/Cu$_{2}$S system that has a higher confinement effect than the pure PbS nanoparticles. The QY was improved in 15 % from PbS to PbS/Cu$_{2}$S nanoparticles. The estimated band (HOMO-LUMO) alignment determined by CV measurements corresponds to a type-I core shell arrangement.