Single-Molecule Phosphorescence and Intersystem Crossing in a Coupled Exciton Plasmon System.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40562699.
- Also identified by DOI 10.1021/acsnano.5c04193 and PMC identifier 12257640.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Scanning the sharp metal tip of a scanning tunneling microscope (STM) over a molecule allows for tuning the coupling between the tip plasmon and a molecular fluorescence emitter. This allows access to local variations in fluorescence field enhancement and wavelength shifts, which are central parameters for characterizing the plasmon-exciton coupling. Performing the same for phosphorescence with molecular-scale resolution remains a significant challenge. In this study, we present the investigation of phosphorescence from isolated Pt-Phthalocyanine molecules by analyzing tip-enhanced emission spectra in both current-induced and laser-induced phosphorescence. The latter directly monitors singlet-to-triplet state intersystem crossing of a molecule below the tip. The study contributes to a detailed understanding of triplet excitation pathways and their potential control at submolecular length scales. Additionally, the coupling of organic phosphors to plasmonic structures is a promising route for improving light-emitting diodes.