Morphological degradation of polymer-fullerene bulk-heterojunction solar cells

Abstract

Organic solar cells offer a wide range of advantages based on their mechanical flexibility, their optical tunability and their ease of production in comparison to conventional photovoltaics. However, elongating their lifetime remains the main challenge after efficiencies exceeding the 10% marker have been recently reported [1]. We focus on the stability of the active bulk-heterojunction layer of polymer-fullerene solar cells. Using in-situ GISAXS and simultaneous current-voltage tracking we have previously shown that the active layer is morphologically unstable during operation of a P3HT:PCBM based solar cell, causing device degradation [2]. In our recent work we observe different degradation mechanisms occurring in other polymer-fullerene blends. This knowledge shows that tailored stabilization methods must be found for each specific material system.