The mesostructured/mesoporous materials have attracted so much interest because of their large pore dimensions and volumes as well as high internal surface areas to use as potential catalysts and separation media.Recently the nanocomposites which are incorporated the organic molecules in the periodic mesostructured/mesoporous materials have received much attention.More efforts have been directed toward the goal of obtaining dye-doped structures for optical applications.In this paper the Rhodamine 6G (Rh 6G) molecules were incorporated in the nanometer pores of MCM-41 to form nanocomposite exhibiting different luminescent property.Such nanocomposite offer new opportunities for controlling the local environments for occluded dye molecules.In this letter we synthesized the polycrystalline powder of the mesostrucure MCM-41 by using cetyltrimothylammonioum bromide as the template.After calcined in air

we obtained the mesoporous MCM-41 framework.The dimensions of the mesopores of the MCM-41 framework are about 3nm.The Rh 6G/MCM-41 assemblies were obtained through ion exchange mixing of the calcined MCM-41 and Rh 6G solution at the concentration of 10

-4

mol/L.The mixtures were stirred for 48h at room temperature.Then the nanocomposite was washed thoroughly with ethanol and dried in air.The nanocomposite was characterized by transmission electron microscopy (TEM)

X-ray diffraction (XRD)

and fluorescence measurements.An obvious blue shift and spectral broadening were observed in the emission of the nanocomposite

compared with Rhodamine 6G in ethanol solution at the concentration less then 10

-10

mol/L.Considering the strong guest-host interaction between the Rh 6G molecules and the MCM-41 mesopores

the blue shift was attributed to the partial localization of the π-electrons in the chromophore.The intramolecular charge-transfer is originated from the strong guest-host interaction between the Rh 6G molecules and the MCM-41 mesopores.And the broad emission of the Rh 6G/MCM-41 can be interpreted as distribution of different site-specific emission.The result indicates that the nanocomposite represents useful property.It suggests a new approach to tunable wavelength range of dye laser.