Probing exciton dissociation in C60/Au(111) using TR-ARPES

ORAL

Abstract

A limiting factor of organic photovoltaic devices is the generation of strongly bound excitons upon photoexcitation which decay quickly (10s - 100s fs). Interfaces often play a role in driving exciton dissociation in devices but the mechanisms that result in efficient charge separation are still not well understood.



While optical techniques have been used to study the ultrafast response of organic semiconductors for several years, a lack of momentum resolution has limited their interpretation. Time- and angle-resolved photoemission spectroscopy (TR-ARPES) is a technique that allows a user to visualize the energy-momentum landscape of a material and enables real-time observation of the material’s response to photoexcitation.



Using TR-ARPES to track the dynamics and resolve the momentum dependent dispersion of the excitations, we are able to probe excitons in C60 and charge separation at the C60/Au(111) interface. We do this for a variety of film thicknesses grown using our two-stage growth method to produce highly-ordered films [1]. This will allow us to better understand the processes that occur post-photoexcitation both at and away from the organic-metal interface.



[1] Tully, Greenwood, Burke, et al., J. Phys. Chem. C, 128, 42 (2024)

*This research was undertaken thanks in part to funding from the Max Planck-UBC-UTokyo Centre for Quantum Materials, and the Canada First Excellence Research Fund in Quantum Materials and Future Technologies Program. This project is also funded by the Gordon and Betty Moore Foundation's EPiQS Initiative, grant no. GBMF4779; the Natural Sciences and Engineering Research Council of Canada (NSERC); the Canada Foundation for Innovation (CFI); the British Columbia Knowledge Development Fund (BCKDF); the Department of National Defense (DND); the Canada Research Chairs Program; and the CIFAR Quantum Materials Program.

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Publication: A. Tully, R. Greenwood, S.A. Burke et al., Two-stage growth for highly ordered epitaxial C60 films on Au(111), J. Phys. Chem. C 2024, 128, 42, 18128–18134

Presenters

  • Rysa Greenwood

    • University of British Columbia
    • The University of British Columbia

Authors

  • Rysa Greenwood

    • University of British Columbia
    • The University of British Columbia

  • Alexandra Tully

    • The University of British Columbia

  • MengXing Na

    • University of British Columbia

  • Bradley G Guislain

    • University of British Columbia

  • Sergey Zhdanovich

    • University of British Columbia

  • Jerry I Dadap

    • University of British Columbia
    • The University of British Columbia

  • Giorgio Levy

    • The University of British Columbia
    • University of British Columbia

  • Arthur K Mills

    • University of British Columbia
    • The University of British Columbia

  • Matteo Michiardi

    • University of British Columbia

  • Andrea Damascelli

    • University of British Columbia

  • Sarah Burke

    • University of British Columbia
    • The University of British Columbia

  • David Jones

    • University of British Columbia
    • The University of British Columbia