Influence of a PbS layer on the optical and electronic properties of ZnO@PbS core-shell nanorod thin films

In the present study, ZnO@PbS core-shell thin film based solar cells have been fabricated by the successive ionic layer absorption and reaction method (SILAR). The assembly consists of zinc oxide (ZnO) nanorods as the core and PbS as the shell, and the thickness of the PbS layer was controlled by varying the number of dipping cycles. The varied PbS layer thicknesses resulted in the shifting of the absorption of ZnO@PbS from the ultraviolet region to the visible region. The PbS layer suppressed the visible emission of ZnO and enhanced the charge separation at the interface. By introducing PbS layers, the charge generation and separation within the ZnO@PbS core-shell nanorod has been improved. The PbS shell on ZnO nanorods improved the short-circuit current (Jsc), open circuit voltage (Voc) and fill factor (FF) that resulted in an enhancement of the photovoltaic device efficiency. A maximum power conversion efficiency of 6.59% was achieved with ten layers of PbS in the ZnO@ PbS@dye thin film based solar cell.