High-efficiency hole-conductor-free rutile TiO2-Nanorod/CH3NH3PbI3 heterojunction solar cells with commercial carbon ink as counter-electrode

Abstract This work demonstrates the fabrication of a high-efficiency, hole-conductor-free, solid-state perovskite solar cell with TiO 2 -nanorod arrays (NRAs) as photoanodes and commercial carbon ink as counter-electrodes. TiO 2 -NRA films of various thicknesses were deposited on FTO electrodes through hydrothermal method for different reaction durations. The effect of the thickness of TiO 2 -NRA films on device performance was investigated in detail. The TiO 2 NRAs/CH 3 NH 3 PbI 3 /C devices based on 688 nm-thick TiO 2 -NRA films exhibited the optimal performance and power conversion efficiency (PCE) of as high as 8.56%. This value is comparable with the PCE of the recently reported TiO 2 NRA/Perovskite/HTM/Au solar cell.