Structural dielectric and spectroscopic investigations of sol gel derived titania poly vinyl pyrrolidine hybrids

Abstract

The development of novel materials and the assessment of their potential applications constitute a major fraction of today s scientific research efforts. Among all the research fields in material science, inorganic-organic hybrids are the most rapidly growing one. Furthermore, it is estimated that nanotechnology has grown into a multibillion dollar industry and may become the most dominant single technology of the twenty-first century. This study focuses on the structural, dielectric and spectroscopic investigations of sol-gel derived Titania/Poly (vinyl-pyrrolidone) hybrids. Various techniques like FTIR spectroscopy, TGA/DTA, XRD, TEM, AFM, SEM, dielectric spectroscopy, UV-VIS spectroscopy and fluorescence spectroscopy were used to assess the structural and optical properties of these hybrid materials. The spectroscopic investigations of the rare earth doped hybrid materials, mainly europium ions and samarium ions are described in respect of their qualitative and quantitative aspects. TiO2/PVP nanocomposites with varying TiO2 concentrations were also characterized for their dielectric response nature. It shows low dielectric constant and dielectric loss with high frequency suggesting an enhanced optical quality for the samples with lesser defects. The conductivity curve shows an increasing tendency with increase in frequency and found to obey Jonscher s power law. Co-doped rare earth cations Tb3+ and Eu3+ aggregated as luminescent centers within the hybrid matrix, in a controlled manner resulted in the white-light phosphors with tunable emission properties. An efficient energy transfer occurs from Tb3+ to Eu3+, due to the energy overlap between Tb3+ and Eu3+ in the hybrid matrix. RGB emission is also observed from the hybrid matrix codoped with rare earth ions (Tb3+ and Eu3+) newline