Adding 0.2 V to the open circuit voltage of organic solar cells by enhancing the built-in potential

We present a systematic device model that reproduces the important features of bulk heterojunction organic solar cells. While examining the model outputs we find that one of the limiting factors in organic solar cells is the reduced built-in potential due to effective pinning of the electrodes relative to the energy gap at the bulk of the device. Having identified this as a problem we suggest a device structure that can enhance the open circuit voltage. Our detailed modeling shows that such a structure can enhance the open circuit voltage as well as the short circuit current leading to above 40% improvement in power conversion efficiency of state of the art organic solar cells. (C) 2015 AIP Publishing LLC.