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 (∼ 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.