Toward Soluble, Air-Stable N-Type Organic Semiconductors

Organic bulk heterojunction solar cells, readily fabricated from blended solutions of donor and acceptor materials, offer lower-cost alternatives to traditional silicon-based solar cells. Despite widespread interest in the contribution of carbon-based photovoltaics to renewable energy efforts, a major deficiency in the general area of organic electronics is the relative scarcity of suitable n-type (acceptor) semiconductors. The functionalized perylene diimides we report are highly soluble, photostable and unreactive towards donor materials such as solubilized pentacene and conjugated polymers. We have used these new materials as acceptor materials in bulk heterojunction solar cells, where initial studies have shown measurable photovoltaic power conversion. Another series of n-type semiconductors, functionalized anthradithiazoles, have been synthesized; their crystal packing and performance in organic thin-film transistors will also be discussed