Synthesis, structural and photoluminescent properties of colloidal semiconductor quantum dots in suspension and on a substrate

Quantum dots (QDs) of CdSe, PbS, InSb semiconductors are synthesized. The laboratory technology of applying layers on the substrate is tested. It is determined from 3D-ACM-topograms that QDs in a layer on a substrate are aggregated into conglomerates with polygonal flattened shape and consisting of tightly packed smaller particles. The experimental characteristics of the photoluminescence spectra are in good accord with the theoretical ones. The quantum output level at QD-PbS and InSb is 5-10 times lower than the best results for colloidal CdSe/CdS quantum dots. A decrease in the quantum yield is observed when transferring quantum dots from a suspension to a substrate, which may be due to the weakening of the dimensional quantization in QD during their aggregation.