Effects of Cu addition to perovskite CH^sub 3^NH^sub 3^PbI^sub 3− x^ Cl x photovoltaic devices with hot airflow during spin-coating

CH3NH3PbI3− x Cl x perovskite-based photovoltaic devices were fabricated by a spin-coating technique using hot airflow, and the effects of CuX (X = I, Br, or Cl) addition to perovskite precursor solutions on photovoltaic properties were investigated. Highly 100-oriented perovskite grains were formed using hot airflow during spin-coating. Compared with pristine perovskite CH3NH3PbI3− x Cl x crystals, grain sizes of the perovskite crystals decreased with the addition of CuBr or CuI, and the coverages of perovskite layers increased, which improved photovoltaic properties. The perovskite solar cell with CuBr added showed the highest conversion efficiency in the present work.