Manipulating the Buried Interfacial Dipole: The Role of Pyridine Acetate-Hydrochloride Isomers in Carbon-Based Perovskite Solar Cells Prepared in Air.

The buried interface between tin oxide and perovskite is the key factor for non-radiative recombination and energy level mismatch, which limits the performance and stability of perovskite solar cells. This work explores a simple interfacial dipole engineering strategy, where three pyridine acetate-hydrochloride (PAH) isomer molecules (2-PAH, 3-PAH, and 4-PAH) are used to modify the SnO2 electron transport layer. The 3-PAH-modified layer can control the work function of tin oxide, achieve the best energy level alignment, and improve the crystallization quality of the perovskite film, thereby effectively suppressing interface recombination and promoting electron extraction. All the devices are prepared in air, and the device optimized by 3-PAH achieved a champion energy conversion efficiency of 14.31% and demonstrated stability. Subsequent to an 800 h placement in an N2 glove box or a 340 h exposure to an air environment, the unencapsulated target devices that were modified by 3-PAH maintained 80.7% and 81.3% of their initial efficiency.