Polymer-fullerene bulk heterojunctions : morphology and its implications on the performance and stability of photovoltaic devices

Abstract

Over the last decade, great improvements have been made within the field of organic BHJ solar cells. It has become clear that the active layer morphology plays a key role in achieving competitive devices. Within this work, the active layer morphology of several polymer:PCBM systems is correlated with the performance and stability of the corresponding solar cells. The morphology of polymer:fullerene blends has to be tuned to obtain state-of-the-art photovoltaic performance. But, an important general conclusion of this work is that the polymer:fullerene blended films are not stable. An increase of temperature can induce and accelerate PCBM diffusion and phase separation. In this work, also some solutions for this problem are investigated. ...