Performance Improvement of Planar Perovskite Solar Cells Using Lauric Acid as Interfacial Modifier

Interfacial defect passivation of perovskite active layer has become an advantageous design that can alleviate interfacial nonradiative recombination, increase the stability and improve the performance of the device. Here, lauric acid as surface passivation agent is introduced on the top of a perovskite active layer. The carboxyl group (-COOH) on lauric acid can coordinate with the Pb2+ on the perovskite and passivate interface defects, which reduces carrier nonradiative combinations and enhances the photovoltaic performance of PSCs. The saturated alkyl chain of lauric acid is covered on the perovskite films, increasingthe moisture resistance of the film and improving the environmental stability of the devices. Consequently, the lauric acid-modified device achieves a power conversion efficiency (PCE) of 21.36% with a high open-circuit voltage (VOC) of 1.181 V and an improved stability, while the pristine device attains only a PCE of 18.08% under the same condition. The results demonstrate a facile and effective strategy to passivate interfacial defects and improve the performance of PSCs by lauric acid modifying.