Phosphorus doped carbon dots additive improves the performance of perovskite solar cells via defect passivation in MAPbI3 films

Perovskites have been widely investigated as absorber layer in photovoltaic technology owing to their excellent properties. For further enhancement of the power conversion efficiencies (PCEs) of MAPbI3 perovskite solar cells, here, we successfully synthesized phosphorus doped carbon dots (P-CQDs) by solvothermal method and inves-tigated their effect as an additive on the perovskite film properties and photovoltaic performance. The results showed that electron-rich phosphorus can act as an excellent core unit in perovskite absorber layer to passivate defects at the surface for improved the crystallization and charge transport properties. Thanks to passivation effect of P-CQDs on perovskite films, as well as the suitable energy band gap values and optical properties of MAPbI3 layer, the device prepared with the addition of 5 vol% of P-CQDs achieved a champion PCE of 13.12% with a high fill factor (FF) of 73.44%, higher than the PCE of 10.71% with a FF of 58.81% for control device.