Device Lifetime Improvement Of Polymer-Based Bulk Heterojunction Solar Cells By Incorporating Copper Oxide Layer At Al Cathode

Organic solar cells are commonly susceptible to degradation in air. We present that insertion of a thin layer of thermally evaporated copper oxide (CuO(x)) between the organic active layer and the Al cathode can greatly extend the lifetime of P3HT:PCBM based bulk heterojunction solar cells. The performance can be further improved by applying an interfacial bilayer of CuO(x)/LiF. Our results suggest that the CuOx functions not only as a charge transport layer but also as a protection layer, which prevents formation of thick organic-Al interdiffusion area. This leads to a more air-resistive cathode/organic interface. (C) 2011 American Institute of Physics. [doi:10.1063/1.3580629]