A contact study in hole conductor free perovskite solar cells with low temperature processed carbon electrodes

Abstract

Hole conductor material (HTM) free photovoltaic devices with graphite electrodes were fabricated at low temperature. An FTO/perovskite contact and TiO2/graphite contact were investigated. The results suggest that the carrier recombination processes resulting from FTO/perovskite and TiO2/carbon contacts affect the device performance greatly. By optimization, a 65 nm TiO2 compact layer with a 380 nm TiO2 mesoporous layer can efficiently decrease the contact between FTO and perovskite materials. The contact between TiO2 and graphite was lowered by the improvement of perovskite coverage. The photo-voltages were enhanced from 0.695 V to 0.820 V and a best efficiency of 10.4% was obtained.