Organic photovoltaic cells with interdigitated structures based on pentacene nanocolumn arrays

Arrays of crystalline and regularly spaced pentacene nanocolumns, with a typical diameter of ca. 150 nm, were fabricated by glancing angle deposition on indium tin oxide substrates. The nanocolumn arrays were used to form large interface area organic heterojunction photovoltaic cells (OPVCs) by spin coating [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor material to fill the voids between nanocolumn. The light to electrical energy conversion efficiency of nanocolumn-based OPVCs was three times higher compared to planar heterojunction OPVCs of the same materials due to a significantly enlarged donor/acceptor interface area where exciton dissociation can occur. Further OPVC performance improvement was achieved through employing a thin pentacene electron-blocking layer before nanocolumn formation, which prevented electron current leakage to the anode.

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► Investigate morphology of pentacene nanocolumn arrays fabricated by glancing angle deposition.
► Presence of interdigitated heterojunction OPVCs achieved by spin-coating PCBM.
► Comparison of three structure OPVCs performance.