Improving the efficiency of ITOc-TiO2/CdS/P3HT:PCBM/PEDOT:PSS/Ag inverted solar cells by sensitizing TiO2 nanocrystalline film with chemical bath-deposited CdS quantum dots

摘要

An improvement in the power conversion efficiency (PCE) of the inverted organic solar cell (ITOc-TiO2/P3HT:PCBM/PEDOT:PSS/Ag) is realized by depositing CdS quantum dots (QDs) on a nanocrystalline TiO2 (nc-TiO2) film as a light absorption material and an electron-selective material. The CdS QDs were deposited via a chemical bath deposition (CBD) method. Our results show that the best PCE of 3.37% for the ITOc-TiO2/CdS/P3HT:PCBM/PEDOT:PSS/Ag cell is about 1.13 times that (2.98%) of the cell without CdS QDs (i.e., ITOc-TiO2/P3HT:PCBM/PEDOT:PSS/Ag). The improved PCE can be mainly attributed to the increased light absorption and the reduced recombination of charge carriers from the TiO2 to the P3HT:PCBM film due to the introduced CdS QDs.