Nanostructured\nElectron-Selective Interlayer for Efficient Inverted Organic Solar Cells

Abstract

We report a unique\nnanostructured electron-selective interlayer comprising of In-doped\nZnO (ZnO:In) and vertically aligned CdSe tetrapods (TPs) for inverted\npolymer:fullerene bulkheterojunction (BHJ) solar cells. With dimension-controlled\nCdSe TPs, the direct inorganic electron transport pathway is provided,\nresulting in the improvement of the short circuit current and fill\nfactor of devices. We demonstrate that the enhancement is attributed\nto the roles of CdSe TPs that reduce the recombination losses between\nthe active layer and buffer layer, improve the hole-blocking as well\nas electron-transporting properties, and simultaneously improve charge\ncollection characteristics. As a result, the power conversion efficiency\nof PTB7:PC₇₀BM based solar cell with nanostructured CdSe\nTPs increases to 7.55%. We expect this approach can be extended to\na general platform for improving charge extraction in organic solar\ncells.