The effect of carbon black in carbon counter electrode for CH3NH3PbI3/TiO2 heterojunction solar cells

Abstract

Carbon counter electrodes (CCEs) based on pure flaky graphite, pure carbon black and graphite/carbon black composites were respectively applied in mesoscopic CH₃NH₃PbI₃/TiO₂ heterojunction solar cells. Crystallinity, conductivity and current–voltage characteristics were measured to study the influence of carbon black in the graphite/carbon black CEs on the perovskite crystal and the photovolatic performance of the devices. Results showed that the content of carbon black in the CCEs could significantly affect the crystallinity and uniformity of the perovskite crystal, leading to different photovolatic performance of the devices. The device with the optimized content of carbon black showed an efficiency of 7.08%, which was much higher than the efficiency of 2.75% obtained by the device based on graphite CE without carbon black.