Preparation and photoluminescence properties of reverse type-I ZnO/PbS core/shell nanorods

ZnO/PbS one-dimensional core/shell nanorods have been fabricated by a two-step growth method. Photoluminescence properties of these samples with different shell thickness are studied in detail. The result reveals that the photoluminescence intensity of the ZnO/PbS core/shell nanorods changes with the increase of thickness of PbS shell. When the shell is very thin, the increase in photoluminescence intensity is attributed to the modification of surface defect state. When the shell becomes thicker, the formation of a reverse type-I band alignment between the core and shell is ascribed to be the factor resulting in the decrease in intensity of the photoluminescence properties.