Hole transport material free-NiO-g-C₃N₄-incorporated methylammonium lead iodide-based perovskite solar cells

The incorporation of p-type semiconductor materials into perovskites is one of the most preferable methods for improving the perovskite layer quality, suppressing carrier recombination and achieving remarkable photovoltaic performance and stability in perovskite solar cells. Herein, NiO-g-C₃N₄ nanocomposites are incorporated with a methylammonium lead iodide (MAPI) precursor to assist in the formation of a high-quality perovskite layer with large grains and fewer defects. The incorporation of NiO-g-C₃N₄ facilitates superior charge generation and charge transfer, reduces recombination at the interface and increases the light harvesting ability by improving the MAPI layer formation and modifying the band position of MAPI. The power conversion efficiency (PCE) of the NiO-g-C₃N₄-MAPI-based PSC increased from 8% to 14%. The maximum PCE of 14.72% was obtained with improved photovoltaic parameters, i.e., a current density (J_sc) of 22.56 mA cm^-2, an open circuit voltage (V_oc) of 0.96 V and a fill factor (FF) of 0.68, for the NiO-g-C₃N₄ (1 : 0.5)-MAPI-based PSC. The NiO-g-C₃N₄-MAPI-based PSCs showed improved stability after 600 hours of storage in an ambient atmosphere.