Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector
Ultrafast Electron?Transfer Via Hybrid States at Perovskite/Fullerene Interface
With two?photon photoelectron spectroscopy, ultrafast electron?transfer of ?100 fs is observed between perovskite and fullerene. The timescale is comparable with hot?electron cooling inside perovskite, leading to efficient electron?transfer overcoming an unfavorable energy?level alignment. The process is achieved with the assistance of interfacial hybrid states, which originate from strong electronic coupling. This finding provides new guidelines for advanced device design.Interfacial charge?transfer between perovskite and charge?transport layers plays a key role in determining performance of perovskite solar cells. The conventional viewpoint emphases the necessity of favorable energy?level alignment of the two components. In recent reports, efficient electron?transfer is observed from perovskite to fullerene?based electron?transport layers even when there are unfavorable energy?level alignments, but the mechanism is still unclear. Here, using an ultrafast in situ two?photon photoelectron spectroscopy, real?time observations of electron?transfer processes at CsPbI3/C60 interface in both temporal and energetic dimensions are reported. Due to strong electronic coupling, a large amount of interfacial hybrid states is generated at the interfaces, aiding fast photoinduced electron?transfer in ?124 fs. This process is further verified by nonadiabatic molecular dynamics simulations and transient absorption experiments. The short timescale explains why electron?transfer can overcome unfavorable energy?level alignments, providing a guideline for device design.
» Publication Date: 31/07/2024
This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº 768737
