Improve Perovskite Solar Cell Stability and Efficiency via Multifunctional Multiple‐Ring Aromatic Dopant Passivation

Abstract

Organic–inorganic perovskite solar cells, as a representative of the new generation of solar cells, have made satisfactory advancements in development over the past few years. However, the low carrier transport characteristics and energy loss brought on by defects severely restrict its development. This study develops a new liquid crystal material 1‐naphthalene acetic acid potassium salt (C12H9KO2, K‐NAA) as a dopant into the MA0.6FA0.4PbI3−xClx material. The presence of free K+ ions in K‐NAA modifies the perovskite lattice gap, and the CO structure can efficiently passivate the Pb2+ defect caused by the absence of coordination. Therefore, the grain boundaries, which serve as points of moisture penetration become blurred, hence suppressing charge trapping/recombination centers and enhancing the film quality and stability. The naphthalene in K‐NAA has a conjugated multiple‐ring aromatic structure. The abundant π‐electron delocalization present in the conjugated structure of the benzene ring may provide an electron‐rich environment outside the connected crystal structure, resulting in field‐effect passivation and effectively enhancing carrier transport performance. Hence, the devices deliver a champion power conversion efficiency (PCE) of 19.86%. After 700 h under the dark at 25 °C and 30% humidity, the optimized unencapsulated device PCE maintains at 92% of its initial efficiency.