Binary Organic Photovoltaic Blends: A Simple Rationale for Optimum Compositions


  • The authors would like to thank Prof. Iain McCulloch, Dr. Martin Heeney, and Maxim Shkunov (Merck Chemicals, UK) for supplying the P3HT homopolymer. P. S. wishes to express his profound gratitude to the Engineering, Materials and Physics (Emphysis) Consortium of Queen Mary, University of London for their invitation to participate in their Prestige Visiting Researcher Programme and to The Leverhulme Trust for granting a Visiting Professorship at Queen Mary, University of London. J. N. and D. D. C. B. acknowledge BP Solar (OSCER), the UK Department of Trade and Industry (Project No. TP/2/RT/6/I/10384) and the UK Engineering and Physical Sciences Research Council Excitonic Supergen Consortium for financial support. Supporting Information is available online from Wiley InterScience or from the author.


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Polymer/small molecule binaries, such as P3HT:PC61BM display eutectic phase behavior with optimum photovoltaic performance at slightly hypoeutectic compositions (with respect to polymer content). Such hypoeutectic blends readily solidify into a finely phase-separated matrix surrounding primary crystals of the small-molecular species. The resulting large interfacial area and component connectivity is a desirable microstructure for bulk-heterojunction solar cells.