Carbon film electrode based square-centimeter scale planar perovskite solar cells exceeding 17% efficiency

Carbon electrode-based perovskite solar cells have shown some advantages in materials cost and long term stability compared to the metal electrode-based devices. Among all the reported carbon electrode techniques, self-adhesive carbon film electrode via press transfer process can achieve high PCE comparable with the Au electrode device in small area perovskite solar cells (similar to 0.1 cm(2)). Herein, we further promote the carbon film electrode to match the practical square-centimeter scale device. Pre-assembled with highly conductive substrates as graphite paper or aluminum foil, the double layered composite carbon electrode can significantly reduce the series resistance, thus retaining the high photoelectric performance of large area device (1 cm(2)). Especially with the graphite paper/carbon film electrode, a highest PCE of 17.02% was obtained, which achieved 92% of the PCE of 18.56% in small device. The soft and compressible nature can be the superiority of graphite paper as conductive substrate in carbon film based electrode compared with aluminum foil.