Emission spectra nanostructures

The preceding chapter showed that many different processes have to be considered if one would like to fully understand the interactions between a fluorophore and a nanostructured metallic template. Depending on the distance regime, classical image theory, electrodynamic theory, nonlocal effects or even wave functions of conduction band electrons leaking out of the metal surface have to be considered. Furthermore, each of the theories gives different results for fluorophores oriented perpendicular or tangential to the metallic surface. Different situations are also expected when either the absorption spectrum or the emission spectrum of the fluorophore overlaps with the plasmon... 

The electronic absorption spectrum of the CuS nanotubes given in Fig. 5a shows the characteristic broad band of CuS in the near IR region, peaking at 1200 nm. The band is attributed to an electron-acceptor state lying within the band gap [17]. A similar broad band has been reported for CuS nanocrystals [27], The photoluminescence spectrum of CuS nanostructures given in Fig. 5b shows a broad band peaking at 560 nm with a shoulder at 480 nm. Bulk CuS is reported to show a broad band centered at 560 nm with a shoulder at 587 nm [17], The absence of any appreciable blue-shift of the emission bands of the CuS nanostructures prepared by us might be due to the formation of chains of nanorods by self-assembly. 

Plasmonic en neering provides the flmdamentals for nanostructure fabrication exploiting the unique optical propolies of certain metals (mainly silver and gold) and advancing the development and applications of plasmon enhanced luminescence. Nanostructures can not only be fabricated to provide enhancement throughout the UV-Vis spectrum but also for near infiared excitation and emissions. 

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