Abstract
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 shy of those considered commercially viable. The shortfall 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 HOMO and LUMO energies to maximize the open circuit voltage (Voc) 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 towards implementing theory, modeling and simulation approaches in combination with results from precision synthesis, characterization and device fabrication as a means to overcome/understand the inherent issues that limit practical applications of organic photovoltaics (OPVs).
