Efficacy of In2S3 interfacial recombination barrier layer in PbS quantum-dot-sensitized solar cells

In2S3 interfacial recombination barrier layer (IBL) via successive ionic layer adsorption and reaction (SILAR) was successfully employed between PbS quantum dots and mesoporous TiO2 in quantum-dot-sensitized solar cells (QDSSCs). In2S3 IBL significantly increased the resistance against back electron transfer from TiO2, resulting an increment in the photocurrent density (JSC) for the cell with single SILAR cycle of In2S3 IBL. Further increase in the number of SILAR cycles of In2S3 IBL deteriorated the JSC, whereas open-circuit voltage sustained the increasing trend. Therefore, an optimal photo-conversion efficiency of similar to 2.2% was obtained for the cell with 2 SILAR cycles of In2S3 IBL, which strategically reached a value of similar to 2.70% after annealing (increased by 40% compared to the control cell without IBL). In2S3 IBL not only improved the recombination resistance and electron life time of the cells, but it also enhanced the photostability of the cells. (C) 2015 Elsevier B.V. All rights reserved.