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Light-induced charge transfer is a crucial step in photosynthesis, photovoltaics and photochemistry, which, however, is usually indirect and inefficient. Several strategies can be applied to achieve a high-efficient charge transfer: (1) in real-space, we have revealed the H-bond network can bridge the proton-coupled charge transfer at water/oxide interface to promote water splitting [1]; (2) in energy scale, we have demonstrated the exciton-plasmon coupling [2] and molecule-plasmon coupling [3] can enhance the charge transfer transitions by tuning the localized plasmon resonances; (3) in time domain, we have achieved coherent charge transfer by two-photon resonance [4]. In this talk, I would like to focus on how quantum coherence can enhance charge transfer. Although it is believed that quantum coherence can enhance function in chemical and biophysical processes [5], direct detection of the ultrafast coherent dynamics is still challenging. We develop the interferometric time-resolved ARPES, which can examine the photoexcited electron phase and population dynamics in energy, momentum and time as the photoinduced quantum state evolves from the donor to acceptor eigenstates. We show bipyridyl ethylene molecule self-assembled monolayer on Ag(111) surface acts as a wet-electron quantum well waveguide for the coherent charge transfer spanning its length. The intermolecular space acting as electron waveguides can preserve coherence for charge separation between donor and acceptor states by ~20 Å on <10 fs time scale [6].
References
[1] Hydrogen-Bond Network Promotes Water Splitting on the TiO2 Surface. Ma et al., J. Am. Chem. Soc. 144, 13565 (2022)
[2] Plasmonic coupling at a metal/semiconductor interface. Tan et al., Nat. Photon. 11, 806 (2017)
[3] Determining structural and chemical heterogeneities of surface species at the single-bond limit. Xu et al., Science 371, 818-822 (2021)
[4] Coherent Electron Transfer at the Ag/Graphite Heterojunction Interface. Tan et al., Phys. Rev. Lett. 120, 126801 (2018)
[5] Using coherence to enhance function in chemical and biophysical systems. Scholes et al., Nature 543, 647-656 (2017)
[6] Coherent charge transfer by intermolecular electron waveguides, Li et al., https://doi.org/10.21203/rs.3.rs-1405372/v1
Prof. Shijing Tan has been working in the field of surface chemistry by taking the advantages of scanning tunneling microscopy (STM), time- and angle-resolved photoemission spectroscopy (TR-ARPES). His research interests focus on coherent energy and charge transfer dynamics at heterogeneous interfaces, such as water/oxide, molecule/substrate, and 2D van der Waals interfaces.
Tencent meeting link: https://meeting.tencent.com/dm/sVg26ntph94J Meeting ID: 108 665 363