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Fluorescence lifetime imaging with near-field scanning optical microscopy
E S Kwak1, T J Kang, D A Vanden Bout
1Department of Chemistry and Biochemistry, Center for Nano- and Molecular Science and Technology, University of Texas at Austin, 78712-1167, USA.
Analytical Chemistry
|July 31, 2001
Summary
This study integrates time-correlated single-photon counting with near-field scanning optical microscopy (NSOM) to image fluorescence lifetimes at nanoscale. The technique reveals how polymer degradation affects light emission, distinguishing between intra- and interpolymer species.
Area of Science:
- Nanotechnology
- Spectroscopy
- Materials Science
Background:
- Near-field scanning optical microscopy (NSOM) offers high-resolution imaging.
- Fluorescence lifetime provides insights into molecular environments.
Purpose of the Study:
- To integrate time-correlated single-photon counting with NSOM for nanoscale fluorescence lifetime imaging.
- To analyze photochemical degradation in polymers using this advanced technique.
Main Methods:
- Utilized a pulsed Ti:sapphire laser for sample excitation.
- Employed time-correlated single-photon counting to measure fluorescence decays.
- Developed NSOM fluorescence imaging with lifetime as a contrast mechanism.
Main Results:
- Achieved spatial resolution below 100 nm for fluorescence lifetime measurements.
- Distinguished between inter- and intrapolymer emitting species in poly(9,9'-dioctylfluorene) (PDOF).
- Observed photochemical degradation-induced quenching of intrachain emission and increase in interpolymer emission.
Conclusions:
- NSOM fluorescence lifetime imaging is effective for studying polymer degradation at the nanoscale.
- The technique can differentiate and map intra- and interpolymer emitting species.
- Photochemical processes significantly alter the fluorescence properties of polymers.