Abstract
Porous alumina (PA) samples are impregnated in rhodamine 6G (Rh6G) solution in order to form Rh6G/PA nanocomposites. The Fourier Transformer Infrared (FTIR) measurements show dispersion of dye molecules into the PA matrix. The investigations are focused on the photoluminescence (PL) properties and PL mechanisms in Rh6G/PA. We have discussed the effect of excitation beam wavelength on the PL, spectrum of Rh6G/PA nanocomposite. It was found that the efficient luminescence of Rh6G/PA nanocomposite is governed by direct excitation and by dipolar interactions between Rh6G molecules with chemical species in alumina crystallites, as has been proved by FTIR measurements. An anti-Stokes photoluminescence (APL) has been observed using a He-Ne laser excitation. We show that its origin is related to a second order phenomenon where phonon absorption plays a key role. (c) 2007 WILEY-VCR Vertag GmbH & Co. KGaA, Weinheim.