121st General Meeting of the KCS

Type Poster Presentation
Area Physical Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code PHYS.P-222
Subject Fluorescence Enhancement and Energy Transfer of Dyes on Homogeneous Silver Colloidal Surfaces
Authors Daedu Lee, jaebeom lee1, Junghyun Song, YOONSOO PANG*
Department of Chemistry, Gwangju Institute of Science and Technology, Korea
1Department of Physics and Photon Science Chemistry, Gwangju Institute of Science and Technology, Korea
Abstract Metal-enhanced fluorescence (MEF) has been of great interest in applications of organic optoelectronics, optical sensors, bioassays, etc. due to large emission enhancements and the increased photostability. MEF is understood as mainly originating from the electric field increase by the surface plasmon of metal nanoparticles and the plasmon coupled emission of metal nanoparticles, but the exact mechanism of the MEF is not yet clear. In our previous study, we found that an ultrafast energy transfer may play an important role in the MEF, but faced the limitation of the inhomogeneity of silver island surfaces for further studies. Thus, homogeneous silver colloidal films (SCFs) composed of silver particles of 70-200 nm in diameter were synthesized in this study and the MEF and ultrafast energy transfer between dyes and nanoparticles were explored by time-resolved fluorescence spectroscopy. The SPR bands of homogeneous SCFs appeared in ultraviolet to visible wavelengths depending on the particle sizes, and exhibited much narrower bandwidth than those of inhomogeneous silver island surfaces. We observed that the fluorescence of DCM and Rh700 were strongly enhanced with SCFs whose SPR bands are overlapped with the emission spectra or placed between the absorption and emission spectra of dyes. By the time-resolved fluorescence measurement and FDTD simulations, relative contributions of the excitation and emission enhancement to the observed fluorescence enhancements of DCM and Rh700 were analyzed. It is found that the MEF of these dyes are predominantly originated from the excitation enhancement by the local electric field increasements.
E-mail leedd1896@gist.ac.kr