Fully crystalline perovskite-perylene hybrid photovoltaic cell capable of 1.2 V output with a minimized voltage loss

A fully crystalline heterojunction of organo-metal-halide perovskite, CH3NH3PbI3−xClx (X 0.24), and perylene constitutes a planar photovoltaic cell that yields a photovoltage exceeding 1.2 V with a single junction cell absorbing up to 800 nm. Here, perylene not only works as a hole conductor but also contributes to photovoltage as a photoconductor. The crystalline plane orientation of perovskite prepared on TiO2 was controlled by thermal annealing such that the lead halide (110) plane that participates in carrier conduction is highly oriented to enhance the photovoltaic performance. The crystal orientation improves the heterojunction structure with perylene. For the best cell with high crystalline orientation, a total voltage loss is significantly minimized to 0.32 V with respect to the absorption band gap of 1.55 eV. The planar crystal cells generate high open-circuit voltages of 1.15–1.22 V, which is close to a theoretical maximal voltage (1.25–1.3 V) described by the Shockley-Queisser efficiency limit. The cell yielded energy conversion efficiency up to 4.96%.