Low-temperature prepared carbon electrodes for hole-conductor-free mesoscopic perovskite solar cells

The low cost graphite/carbon black counter electrodes were prepared under low-temperature for hole-conductor-free mesoscopic perovskite solar cells. Different mass fraction of carbon black particles in the interspace of graphite flakes not only modulates the connection of carbon black and graphite flakes, but also guarantees the good contact between the counter electrode and perovskite layer, which obviously improves the charge transport properties of the cells. The electrochemical impedance spectra and incident photon-to-current conversion efficiency study show evidences of it. Based on the optimized low-temperature carbon electrode (LTCE) with a thickness of 5 μm, power conversion efficiency about 7.29% and good stability are achieved for the hole-conductor-free mesoscopic perovskite solar cells. The abundant availability and excellent properties of such carbon materials based LTCEs offer a wide prospect for its further applications in perovskite solar cells.