Enhancing the performance of polymer solar cells using CuPc nanocrystals as additives.

There is an increasing interest in the use of different nanoparticles as additives in polymer solar cells for enhancing the light absorption of active layers as well as their power conversion efficiency (PCE). In this paper, we report a PCE enhancement by simply adding copper phthalocyanine (CuPc) nanocrystals into photovoltaic devices based on a poly(3-hexylthiophene) (P3HT): fullerene system. Two kinds of device structure were studied: the first one is a CuPc nanocrystal suspension spin coated on the poly(3,4-ethylenedioxythiophene) polystyrene sulfonate-coated substrate; the second one is the CuPc nanocrystal suspension added into the active layer solutions. It is proved that incorporating organic semiconductor nanocrystals into the active layer can help trap light and enhance the crystallinity of the active layers, thus improving the device performance. This strategy might be generally compatible with a broad range of organic photovoltaic materials and offers an effective approach to enhance the device performance.