TiOx/Al bilayer as cathode buffer layer for inverted organic solar cell

Abstract

Titanium oxide (TiOx) modified with a thin layer of Al was used as an electron transporting layer in an inverted organic solar cell based on the P3HT/PCBM blend. The thin Al layer was shown to improve the TiOx surface properties, decreased the work-function of TiOx, increased the built-in voltage, and facilitated electron extraction. As a result, good device performance with power conversion efficiency of 3.6%, open circuit voltage of 0.60 V, short circuit current of 9.13 mA/cm2, and fill factor of 0.66 was achieved. The light soaking problem was eliminated compared to the TiOx only device.