Chloride Inclusion and Hole Transport Material Doping to Improve Methyl Ammonium Lead Bromide Perovskite-Based High Open-Circuit Voltage Solar Cells

Low-cost solar cells with high V-OC, relatively small (E-G - qV(OC)), and high qV(OC)/E-G ratio, where E-G is the absorber band gap, are long sought after, especially for use in tandem cells or other systems with spectral splitting. We report a significant improvement in CH3NH3PbBr3-based cells, using CH(3)NH(3)PbBr(3-)xCl(x), with E-G = 2.3 eV, as the absorber in a mesoporous p-i-n device configuration. By p-doping an organic hole transport material with a deep HOMO level and wide band gap to reduce recombination, the cell's V-OC increased to 1.5 V, a 0.2 V increase from our earlier results with the pristine Br analogue with an identical band gap. At the same time, in the most efficient devices, the current density increased from similar to 1 to 4 mA/cm(2).