P-type doping of rGO/NiO composite for carbon based perovskite solar cells

The hole transport layer (HTL) free carbon based perovskite solar cells (Carbon PSC) are known for low cost, good stability and commercial manufacturing technology . Compared to the structure of traditional cells, the carrier transport performance between the absorber layer and the carbon electrode (CE) is poor. As an excellent P-type material, NiO has been doped in CE for obtaining a better performance of PSCs. However, NiO will inevitably reduce the conductivity of the CE due to the poor conductivity, thus failing to fully exploit the advantages of NiO in hole extraction. In this paper, rGO/NiO composites were successfully prepared by doping rGO with good conductivity, which not only improved the conductivity of the CE, but also ensured good hole extraction of the doped CE. The carrier transport in the cell was significantly improved, resulting in 32% increase in the short circuit current density (J sc ). The performance of perovskite solar cells was optimized by doping the CE, and the power conversion efficiency (PCE) of the cell was increased from 5.48% to 8.50%.