Targeted Design of Surface Configuration on CsPbI3 Perovskite Nanocrystals for High-Efficiency Photovoltaics

The advanced optoelectronic properties of the emerging halide perovskite nanocrystals (PNCs) have brought forth new opportunities for photovoltaic applications. However, their dynamic ligand binding and fragile crystal structure make the conventional NC surface manipulation strategies inaccessible. It is urgent to specially design the surface configuration of PNCs for high-efficiency photovoltaics. Herein, we develop the synthesis of CsPbI3 PNCs with a guanidinium (GA)-anchored surface based on a vacancy-suppressed ternary-precursor method. The hydrogen bond between GA(+) and surrounding iodine can reinforce the PNC surface and improve surface passivation. Furthermore, the short GA(+) can ensure high interdot coupling in the PNC film. Therefore, the obtained PNC film can realize both a low trap density and high carrier mobility. Consequently, a champion power conversion efficiency (PCE) of 15.83% can be achieved. In addition, the production yield of our method is significantly higher than that of the conventional method, which makes the synthesis protocol more suitable for future scalable manufacturing.