Protonated Cyclohexylamine as an Effective Passivation Layer for High-Performance Perovskite Solar Cells

Abstract Due to the presence of numerous defects in polycrystalline perovskite films, the performance of the target devices is limited. This work suggests using the –NH3+ produced during the protonation of cyclohexylamine hydrochloride (CHLCl) to passivate perovskite film interface flaws and improve device performance. The device interfacial defects are passivated by hydrogen bonding between the functional groups of the passivants and uncoordinated ions in the films. Meanwhile, the cyclohexylamine hydrochloride layer results in a smoother perovskite surface, which facilitates the charge transport in the devices. The modified device obtained a champion power conversion efficiency (PCE) of 21.53%, which is 11.21% higher than that of the control device (19.36%). The modified device preserved 80% of initial PCE after 720 h, compared to 58% for the control device. Dynamic simulations and DFT calculations revealed that CHLCl exhibits enhanced interfacial migration behavior and moderate adsorption energy, enabling effective defect passivation and improved interfacial charge transport. It establishes a common design paradigm for efficient and low-cost perovskite materials.