Ye, F.; Zhang, S.; Lang, F.; Raoufi, M.; Liang, J.; Levine, I.; Hempel, H.; Menzel, D.; Zu, F.; Albrecht, S.; Korte, L.; Messmer, C.; Schön, J.; Glunz, S.W.; Unold, T.; Koch, N.; Neher, D.; Ye, D.; Wu, Y.; Stolterfoht, M.: Minimizing Recombination at the Perovskite/C60 Interface through a Volatile Highly Dense Molecular Interlayer. ACS Energy Letters 10 (2025), p. 2942-2951
10.1021/acsenergylett.5c00615
Open Access Version
Abstract:
Advancing inverted perovskite solar cells requires effective strategies to mitigate nonradiative recombination at the perovskite/C60 interface. Here, we report a volatile material that forms a thin, dense interlayer that essentially eliminates the C60-induced nonradiative interfacial recombination loss despite not directly passivating the perovskite surface. Ultraviolet photoelectron spectroscopy highlights that the molecule forms a positive dipole layer on the surface that aligns the perovskite and C60 energy levels for electron conduction. Furthermore, the molecule’s volatile nature allows the use of a high-concentration solution that enables a high surface coverage (likely >99%) without increasing the thickness. The combination of these two effects yields an effective approach to suppressing interface recombination. The resulting triple cation perovskite solar cells achieved a power conversion efficiency of >25% and the devices maintain >90% of their initial efficiency after 1200 h of operation. Furthermore, the molecule is broadly applicable to various perovskite compositions and bandgaps.