Minimizing Recombination at the Perovskite/C<sub>60</sub> Interface through a Volatile Highly Dense Molecular Interlayer
Fangyuan Ye, Shuo Zhang, Felix Lang, Meysam Raoufi, Jianjun Liang, Igal Levine, Hannes Hempel, Dorothee Menzel, Fengshuo Zu, Steve Albrecht, Lars Korte, Christoph Messmer, Jonas Schön, Stefan W. Glunz, Thomas Unold, Norbert Koch, Dieter Neher, Dongting Ye, Yongzhen Wu, Martin Stolterfoht
Abstract
High Resolution Image Download MS PowerPoint Slide Advancing inverted perovskite solar cells requires effective strategies to mitigate nonradiative recombination at the perovskite/C 60 interface. Here, we report a volatile material that forms a thin, dense interlayer that essentially eliminates the C 60 -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 C 60 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.