The performance of perovskite solar cells (PSCs) is critically constrained by nonradiative recombination at the perovskite/charge-extraction interfaces, which limits their approach to the thermodynamic efficiency limit. Although extensive efforts have focused on passivating surface defects, the role of interfacial energy-level mismatch in driving nonradiative losses remains insufficiently understood. In this work, we investigate the impact of valence band maximum (VBM) offsets between hole-selective layers and perovskites on the nonradiative recombination losses in PSCs by tailoring the terminal groups of hole-selective materials (HSMs). Our findings reveal that the minimized energetic barrier at the hole-selective interface is conducive to achieving the maximum quasi-Fermi level splitting (QFLS) in perovskites. Through precise energy-level alignment at the buried HSM/perovskite interface via terminal group engineering, we achieved high power conversion efficiency (PCE) of 26.88% and 21.87% for PSCs based on 1.53 and 1.72 eV perovskites, respectively, with open-circuit voltage (VOC) value reaching 95% and 91% of their Shockley-Queisser limit, respectively. Our results provide valuable insights for designing hole-selective molecules and elucidating the relationship between nonradiative recombination losses and energy level alignment across different perovskite compositions.
Zhang et al. (Sun,) studied this question.