Abstract

In order to identify the factors that limit the efficiency of bulk heterojunction (BHJ) solar cells, a model describing the electrical properties of BHJs is proposed. In the metal-insulator-metal model the generation and transport processes in the BHJ are treated as if occurring in one virtual semiconductor. The main virtue of this model is that it relates solar cell performance to basic physics and material properties such as charge carrier mobilities.

With respect to improving these devices, it is demonstrated that the optimal band gap of the absorbing polymer is close to 1.9 eV. Moreover, although still not as efficient as inorganic solar cells, polymer/fullerene based devices can reach an efficiency of more than 10%.

Hybrid organic/inorganic solar cells, based on inorganic nanoparticles and conjugated polymer are an auspicious alternative to polymer/fullerene devices. The transport properties of polymer/zinc oxide nanocrystals blend films are investigated.