Efficient inverted perovskite solar cells with CuSeCN as the hole transport material

We demonstrate herein a mixed solvent containing organic amines and water for the solution processing of CuSeCN and apply it as the hole-transport material for stable and efficient inverted perovskite solar cells for the first time. The obtained CuSeCN film is characterized with X-ray diffraction spectrum, X-ray photoelectron spectroscopy, scanning electron microscope, and current-potential characteristics. High-quality perovskite film can be formed on the CuSeCN film obtained from the spin-coating of CuSeCN solution in a mixture solvent of H2O, ethanolamine (ETA), ethylenediamine (EDA), diethanolamine (DTA) with volume ratio of 2:6:1:1. The CuSeCN-based perovskite solar cell yields power conversion efficiency of 15.61% at forward scan and 15.97% at reverse scan with negligible hysteresis and good stability. As compared to the typically used thioether-based solvents for the solution processing of CuSCN, the mixture solvent proposed in this work is less volatile and much cheaper, which is critical for practical applications of perovskite solar cells.