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Exciton Quenching at Grain Boundaries in C60 Thin Films
Rysa Greenwood1,2, Bradley G Guislain1,2, MengXing Na1,2
1Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
The Journal of Physical Chemistry Letters
|October 24, 2025
Summary
Grain boundaries in C60/Au(111) thin films shorten exciton lifetimes and increase annihilation. This impacts organic optoelectronic device performance, emphasizing the need for structural control in film quality.
Area of Science:
- Materials Science
- Surface Science
- Organic Electronics
Background:
- Exciton lifetimes are crucial for organic optoelectronic device efficiency.
- Understanding exciton dynamics in thin films is essential for device optimization.
Purpose of the Study:
- Investigate the impact of multiple rotational domains and grain boundaries on exciton dynamics in C60/Au(111) thin films.
- Correlate structural properties with exciton behavior.
Main Methods:
- Time- and angle-resolved photoemission spectroscopy (TR-ARPES) to study exciton dynamics.
- Scanning tunneling microscopy (STM) to analyze film structure and electronic properties.
Main Results:
- Films with multiple rotational domains show reduced exciton lifetimes.
- Increased susceptibility to exciton-exciton annihilation was observed in polycrystalline films.
- Grain boundaries lead to electronic structure changes and a locally reduced dielectric constant.
Conclusions:
- Grain boundaries significantly impact exciton dynamics and reduce exciton lifetimes.
- Exciton funneling and additional decay channels at grain boundaries contribute to lifetime reduction.
- Precise structural control of thin films is vital for enhancing organic optoelectronic device performance.
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