Santhi, A; Umadevi, M; Ramakrishnan, V; Radhakrishnan, P; Nampoori, V P N(Elsevier, 2004)
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Abstract:
Nano structured noble metals have very important applications in diverse fields as photovoltaics, catalysis, electronic and magnetic devices, etc. Here, we report the application of dual beam thermal lens technique for the determination of the effect of silver sol on the absolute fluorescence quantum yield (FQY) of the laser dye rhodamine 6G. A 532 nm radiation from a diode pumped solid state laser was used as the excitation source. It has been observed that the presence of silver sol decreases the fluorescence quantum efficiency. This is expected to have a very important consequence in enhancing Raman scattering which is an important spectrochemical tool that provides information on molecular structures. We have also observed that the presence of silver sol can enhance the thermal lens signal which makes the detection of the signal easier at any concentration.
Achamma, Kurian; Nibu, A George; Binoy, Paul; Nampoori, V P N; Vallabhan, C P G(Taylor & Francis, 2002)
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Abstract:
In this paper we report the use of the dual beam thermal lens technique as a quantitative
method to determine absolute fluorescence quantum efficiency and concentration
quenching of fluorescence emission from rhodamine 6G doped Poly(methyl
methacrylate) (PMMA), prepared with different concentrations of the dye. A
comparison of the present data with that reported in the literature indicates that the
observed variation of fluorescence quantum yield with respect to the dye
concentration follows a similar profile as in the earlier reported observations on
rhodamine 6G in solution. The photodegradation of the dye molecules under cw laser
excitation is also studied using the present method.