Inverted organic solar cells with ZnO thin films prepared by sol-gel method

The influences of buffer layers on the performance of hybrid solar cells that are fabricated with an active layer blend of poly (3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-buytyric acid methyl ester (PCBM), were investigated. The ZnO thin films were used as an electron transport layer in solar cells to improve the photovoltaic performances. To explore the effects of ZnO film thickness, ZnO thin films were deposited as an electron transport layer by spin coating them one to four times at 4000 rpm using zinc acetate dehydrate that was dissolved in a mixed solution of 2-methoxyethanol and ethanolamine. We fabricated lOSCs on PES substrate, consist of Au/MoO₃/PCBM:P3HT/ZnO/ ITO. The optical property of the ZnO buffer layers was investigated. Furthermore, we found the optimum ZnO buffer layer by using the sol-gel method to enhance the performance of the solar cells.