Solution-Processed Planar Perovskite Solar Cell Without a Hole Transport Layer.

Solar cells with a structure of ITO/ZnO/CH3NH3PbI3/graphite/carbon black electrode were fabricated by spin coating at ambient conditions. PbI2 thin films were converted into CH3NH3PbI3 perovskite by reacting with CH3NH3I in solution. The incorporation of electrochemically exfoliated graphite improved the fill factor, open circuit potential and short circuit current density. The best device yielded 10.2% power conversion efficiency.