Structural and spectral investigations of Rhodamine (Rh6G) dye-silica core–shell nanoparticles

Abstract

Rhodamine (Rh6G) dye-silica core–shell nanoparticles (DSCSNPs) have been prepared by the controlled hydrolysis and condensation of single silica precursor tetraethylorthosilicate (TEOS) using the sol–gel method. Scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analysis reveal that dye molecules are entrapped in silica (SiO2) shell resulting into core–shell particles of ∼30nm diameter. These particles are also characterized by X-ray diffraction and Fourier transforms infrared spectroscopy. The results indicate that core–shell particles are all in spherical shape and have a narrow size distribution. The fluorescent and optical properties of core–shell particles have been investigated using fluorescence and UV–Visible absorption spectra. The photoluminescence in solid or liquid medium occurs at the same wavelength. The SiO2 shell restricts the leakage and photobleaching of dye efficiently. These core–shell nanoparticles are found to be highly luminescent and stable.