Molybdenum Oxide Particles Doped in Hole Transport Layer to Enhance the Efficiency of Flexible Polymer Solar Cells

Abstract

Five PEDOT:PSS:MoO3 volume ratios (1:1, 1:2, 1:3, 1:4, 1:5) hybrid hole transport layer (HTL) were prepared by solution processed method. The cell structure was PET/ITO/PEDOT:PSS:MoO3/P3HT:PCBM/Ca/Al. We investigated the effect of MoO3 added into the traditional PEDOT:PSS hole transfer layer on the photovoltaic performance. From these results, we found that the short circuit current density (Jsc), fill factor (FF) and power conversion efficiency PCE of the cells with MoO3 are always higher than those of cell without MoO3.The short-circuit current density, fill factor and power conversion efficiency of cells increased with increasing MoO3 volume ratio from 1:1 to 1:3 and then decreased slightly when the volume ratio increased to 1:4 and 1:5. The cell with 1:3 volume ratio exhibited the highest Jsc of 9.41 mA/cm2, an increase of 22%, and the highest PCE of 2.74%, an increase of 39%, compared to the controlled cell using PEDOT:PSS layer. The addition of MoO3 increased the probability of exciton dissociation due to its high hole mobility, thereby enhancing the Jsc and FF.