Ultrafast Intersystem Crossing in Icosahedral-Core Metal Nanoclusters
Hongmae Heo1, Jieun Lee1, Yuhyeon Kim1
1Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea.
Journal of the American Chemical Society
|March 20, 2026
Summary
Metal nanoclusters (NCs) rapidly form triplet states within 100 femtoseconds after photoexcitation. Different NC structures exhibit unique energy dissipation pathways, guiding future material design for energy applications.
Area of Science:
- Physical Chemistry
- Materials Science
- Nanotechnology
Background:
- Atomically precise metal nanoclusters (NCs) bridge molecular and nanoscale materials.
- Understanding NC excited-state relaxation is crucial for developing predictive structure-photophysics relationships.
Purpose of the Study:
- To resolve the earliest excited-state energy dissipation pathways in metal nanoclusters.
- To elucidate the mechanistic role and timing of triplet-state formation in NCs.
Main Methods:
- Broadband transient absorption spectroscopy.
- Femtosecond-nanosecond time-resolved measurements.
- Utilized prototypical Au25, Ag25, and Au13 nanoclusters as model systems.
Main Results:
- Demonstrated ultrafast intersystem crossing (sub-100 fs) populating triplet states in metal NCs.
- Observed distinct transient spectral signatures confirming rapid triplet formation.
- Identified structure-dependent relaxation pathways, including vibrational relaxation in flexible motifs.
Conclusions:
- Established a revised mechanistic picture of excited-state energy dissipation in icosahedral-core metal NCs.
- Unified the excited-state energy dissipation framework for triplet-emissive NCs.
- Provided mechanistic guidelines for designing NCs for energy conversion and photochemical applications.
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