Can computational approaches aid in untangling the inherent complexity of practical organic photovoltaic systems?

Organic materials, in particular conjugated polymers, have recently become the subject of extensive research for photovoltaic device applications. This increase of interest is primarily the result of their potentially low manufacturing cost, compatibility with flexible substrates, diverse chemical tunability, scalability, and ease of processing currently available for suitable bulk heterojunction (BHJ) construction. However, to date, these materials have not been able to exceed power conversion efficiencies (PCE) beyond 5-9%, values short of those considered commercially viable. The deficit in PCE appears to derive from a combination of physicochemical and device complexities associated with inadequate hole transport mobility, solubility and miscibility with an appropriate acceptor, narrow electronic band gap for efficient solar light harvesting, appropriate highest occupied molecular orbital (HOMO) and lowest unoccopied molecular orbital (LUMO) energies to maximize the open-circuit voltage (V _oc) and electron transfer to the acceptor, and in particular the control of the multidimensional problem of BHJ morphology. In this review article, we provide an overview of some of the recent progress toward implementing theory, modeling, and simulation approaches in combination with results from precision synthesis, characterization, and device fabrication as a mean to overcome/understand the inherent issues that limit practical applications of organic photovoltaics.