Perylenes in Organic Photovoltaics

Abstract

As metal-free dyes, perylene derivatives have been widely applied in various optical devices owing to their outstanding chemical, thermal and photochemical stability and non-toxicity. Moreover, the exploitation of perylene dyes for organic solar cells can be traced back to the first efficient organic photovoltaic cell fabricated by Tang where phthalocyanine and perylenedibenzimidazole were applied as active materials with a reasonable power conversion efficiency of up to 1%. Their tunable solubilities as well as optical and electronic properties render perylene dyes available for all kinds of organic solar cells, including organic heterojunction and hybrid solar cells. Because of their outstanding p-conjugated planar core with imide or amidine groups, perylene compounds have high electron affinities and can thus accept electrons from most donor compounds. Soluble perylene dyes have been widely used in solution-processable polymer solar cells, whereas perylene pigments can be employed in bilayer heterojunction solar cells via sublimation. Perylene compounds can also couple to other electrondonating groups to form donor-acceptor oligomers or polymers for photovoltaic applications. Using the anhydride or carboxylic acid groups as anchors, perylene molecules are able to be applied in dye-sensitized solar cells as well. With the consideration of the uniqueness of perylenes, the present article reviews the development of perylenes in organic photovoltaics.