Inverted organic solar cells with ITO electrodes modified with an ultrathin Al2O3 buffer layer deposited by atomic layer deposition

We report on the properties of inverted polymer solar cells using an ultrathin Al2O3 buffer layer on indium tin oxide (ITO). The ultrathin Al2O3 layer, deposited by the atomic layer deposition method, was found to reduce the work function of ITO and turns ITO into an electron-collecting electrode. The current density–voltage characteristics of unexposed devices showed an s-shape kink. The kink was eliminated upon exposure to ultraviolet (UV) illumination. Inverted solar cells based on P3HT:PC60BM yielded a fill factor of 0.64 and a power conversion efficiency of about 2.8% estimated for 100 mW cm−2 simulated AM 1.5 illumination.

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