Title :
The Metal-Enhanced Fluorescence of CdTe Quantum Dots under the Excitation of Femto Second Laser
Author :
An, L.M. ; Han, X.T. ; Chen, X.L. ; Qu, Y.Q. ; An, W.Y. ; Li, X.G. ; He, L.Z. ; Wang, G.R.
Author_Institution :
Coll. of Phys. Sci. & Technol., Heilongjiang Univ., Harbin, China
Abstract :
This paper presents an investigation on the fluorescent properties of semiconductor CdTe quantum dots (QDs) self-assembled on the surface of PVP (polyvinylpyrrolidone) capped silver nanoparticles (NPs) film by ligand field effect under the two photons excitation of 800nm femto second laser. A significant enhancement by 4.5-fold in the integrated fluorescence intensities, red shift of fluorescence peak and obvious decrease of lifetime were observed in the CdTe QDs assembled on the Ag NPs film in comparison with the pure CdTe QDs on the glass. The fluorescence enhanced factor is larger on the solid film than in the liquid. The fluorescence enhancement factor and red shift were found to depend on the Ag NPs concentration. The fluorescence enhancement was contributed to high localized electromagnetic field generated by the surface plasma on the Ag NPs and the change of surface trap state of CdTe QDs originating from plasma oscillations in the Ag NPs.
Keywords :
II-VI semiconductors; cadmium compounds; crystal field interactions; fluorescence; photoexcitation; radiative lifetimes; red shift; self-assembly; semiconductor growth; semiconductor quantum dots; surface plasmon resonance; two-photon processes; wide band gap semiconductors; Ag nanoparticle concentration; CdTe; Si; femtosecond laser excitation; fluorescence enhanced factor; fluorescence enhancement factor; fluorescence peak; fluorescent properties; high localized electromagnetic field; integrated fluorescence intensities; ligand field effect; metal-enhanced fluorescence; plasma oscillations; polyvinylpyrrolidone capped silver nanoparticle film surface; red shift; self-assembly; semiconductor CdTe quantum dots; solid film; surface plasma; surface trap state change; two photon excitation; wavelength 800 nm; Films; Fluorescence; Laser excitation; Nanoparticles; Optical surface waves; Plasmas; Silver;
Conference_Titel :
Photonics and Optoelectronics (SOPO), 2012 Symposium on
Conference_Location :
Shanghai
Print_ISBN :
978-1-4577-0909-8
DOI :
10.1109/SOPO.2012.6270974
