Highly efficient p–i–n type organic photovoltaic devices

Abstract We present results on p–i–n-type photovoltaic devices based on donor–acceptor organic small molecule blends and doped wide-gap charge transport layers. The doped transport layers are formed using a high vacuum co-evaporation deposition technique (i.e. co-sublimation of matrix and dopant). Solar cell devices have been fabricated based on a blend of zinc-phthalocyanine as donor (D) and fullerene (C60) as electron acceptor (A) with doped charge transport layers. Optionally, a layer of neat layer of a perylene dye, perlenetetracarboxylic-bis-benzimidazole, is added to extend the absorption spectrum of the active layer system. The energy conversion efficiency of these cells under 1 sun, standard AM1.5 illumination (100 mW/cm2) is up to 1.9%. This represents an almost twofold improvement as compared to previously reported cells with similar active layer system in a conventional architecture. In this report, I–V characteristics, power conversion efficiencies, the dependence of short circuit current on incident white light intensity and absorption spectra of the active layer system are discussed.