Effect of Sol-Gel Prepared ZnO Electron Selective Layer on the Performance of Inverted Organic Solar Cells

Abstract

ZnO buffer layer was prepared as electron selective layers (ESL) for photo-induced electron transport and hole blocking in inverted organic solar cells (IOSCs) by sol-gel process. The effects of thickness and surface roughness of ZnO ESL on the performance of IOSCs were investigated. Power Conversion Efficiency (PCE) of the IOSC strongly varied as a function of ZnO film thickness and surface roughness, in particular, when the film thickness was <70 nm, increase in the surface roughness enhanced photovoltaic performances. It is demonstrated that optimization of the electrode thickness and roughness is essential for obtaining better performance of organic photovoltaic cells.

Keywords:

• Film thickness
• inverted organic solar cells
• surface roughness
• ZnO sol-gel