Polymer Photovoltaic Optimizations Via Molecular Structure, Morphology, and Orbital Level Fine Tuning

The optimization approaches of polymeric solar cells in both space and energy regimes are described at molecular and orbital levels. For instance, it was found the photoelectric conversions of a donor-bridge-acceptor-bridge type block copolymer is much better then the corresponding donor/acceptor blend under identical conditions, and that was mainly attributed to spatial morphology improvement in the block copolymer. At energy and electron transfer dynamic regime, preliminary theoretical analysis revealed that the photo induced charge separation appears most efficient when the frontier orbital offset is equal to the sum of the charge separation reorganization energy and the exciton binding energy. The degree of orbital overlap is critical for mechanisms of charge carrier generation and transport. The donor/acceptor charge separation model is applicable to both excited and ground state charge separation cases