Effect of Side-Group-Regulated Dipolar Passivating Molecules on CsPbBr3 Perovskite Solar Cells

Interfacial passivation of defective perovskite films with a dipole molecule shows a great potential for high-efficiency perovskite solar cells (PSCs). Herein, by regulating the side group of an aniline-based molecule with an electron-withdrawing nitiyl (-NO2) or electron-donating methoxyl (-OCH3), the binding energy between -NH2 and under-coordinated Pb2+ in the CsPbBr3 lattice is reinforced, and the dipole-moment-induced surface energy level reconstruction allows for efficient hole extraction for the -OCH3-tailored molecule because of the changed intramolecular electron distribution, whereas -NO2 displays the opposite effect. Finally, the all-inorganic CsPbBr3PSC achieves a power conversion efficiency (PCE) of 9.814% with an open-circuit voltage (V-oc) of 1.632 V and an excellent stability in both high humidity and light irradiation. Upon doping Sm3+ into CsPbBr3, the PCE and V-oc are further increased to 10.75% and 1.675 V. This work confirms the importance of a side group on an interface dipole molecule to maximize the charge scavenging, especially for V-oc improvement.

Automated summary

This study demonstrates the importance of regulating the side group of a dipole molecule for interfacial passivation and surface energy level reconstruction of CsPbBr3 perovskite films to achieve efficient hole extraction and improve power conversion efficiency.