Analysis of photovoltaic mechanisms of organic solar cells by quantum chemistry
This article introduces recent studies on the charge separation mechanism in organic solar cells. One of the important questions for organic solar cells is how free electrons and holes are generated, overcoming the Coulomb attraction at donor-acceptor interfaces. We carried out a combined electronic structure and quantum dynamical analysis that captures the elementary events from the exciton dissociation to the free carrier generation at polymer/fullerene donor-acceptor heterojunctions. Our calculations show that experimentally observed efficient charge separations can be explained by a combination of two effects: first, the delocalization of charges, which substantially reduces the Coulomb barrier, and second, the vibronically hot nature of the charge transfer state which promotes charge dissociation beyond the barrier.
- 1 The Universiyt of Tokyo