ENHANCED DYE FLUORESCENCE OVER SILVER ISLAND FILMS - ANALYSIS OF THE DISTANCE DEPENDENCE

被引:285
作者
KUMMERLEN, J [1 ]
LEITNER, A [1 ]
BRUNNER, H [1 ]
AUSSENEGG, FR [1 ]
WOKAUN, A [1 ]
机构
[1] KARL FRANZENS UNIV,INST EXPTL PHYS,A-8010 GRAZ,AUSTRIA
关键词
D O I
10.1080/00268979300102851
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Fluorescence intensity enhancement has been studied for several coverages (10(-3) to 1 monolayer) of Rhodamine 6G separated from a silver island him by quartz spacer layers of varying thickness. When the dye film is brought into the proximity of the island film support, a first enhancement maximum is observed at approximate to 60 nm spacer thickness. For smaller distances, decrease in the enhancement is followed by a second maximum at 5-1O nm interlayer thickness. The magnitude of the latter maximum exhibits a pronounced dependence on dye coverage. The far-field enhancement maximum is due to an increase in fluorescence quantum yield induced by the presence of the island film substrate, combined with a resonant excitation phenomenon due to collective action of the islands. This effect is analysed in terms of stratified medium theory, in which the island film is represented by a suitable model for the effective dielectric constant. The short distance enhancement results from competition between the strongly amplified local field around the spheroidal metal particle and the radiationless loss of excitation energy by transfer to nonradiating particle surface plasmons.
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页码:1031 / 1046
页数:16
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