Study of structural transformation in TiO2 nanoparticles and its optical properties

• Published in: Journal of alloys and compounds 2013-02, Vol.549, p.114-120
• Main Authors: Tripathi, Anand Kumar, Singh, Manish Kumar, Mathpal, Mohan Chandra, Mishra, Sheo Kumar, Agarwal, Arvind
• Format: Article
• Language: English
• Subjects: Anatase; Chemical synthesis methods; Compressive properties; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Crystallites; Energy bands; Exact sciences and technology; Materials science; Methods of nanofabrication; Nanocrystals and nanoparticles; nanomaterials; Nanostructure; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Photoluminescence; Physics; Spectroscopy; Strain; TiO2; Titanium dioxide; XRD
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.09.012

► One step process for synthesizing pure and mixed phase TiO2 nanoparticles. ► The crystallite size of prepared TiO2 at different temperature is in the range of 19–68nm. ► The tensile strain has been observed below 600°C and converted into compressive strain at 700°C. ► Photoluminescence spectroscopy (PL) exhibits the change in PL intensity with phase change. ► Different trends have been observed in emission edges. Pure and mixed phase TiO2 have been prepared by sol–gel method; calcinated at four different temperatures. The influence of calcination temperature on crystallite size, morphology, band gap and luminescence properties of resultant material have been investigated. Different trends were observed in the phase transformation, particle growth, shift in energy band gap and in luminescence with the change in tensile strain to compressive strain of the prepared TiO2 nanomaterial. X-ray diffraction (XRD) showed that prepared nanocrystals have pure anatase and anatase-rutile mixed structures. The prepared samples having crystallite size between 19nm to 68nm were observed at different calcination temperatures. Williamson-Hall plot results indicate the presence of tensile strain at 400, 500 and 600°C while compressive strain at 700°C. Scanning electron microscopy (SEM) shows that the particles are non-uniform. Ultraviolet-Visible spectroscopy (UV-Vis) is used to calculate the energy band gap of materials and it has been observed that the band gap decreases with increase in temperature. Fourier transform infrared spectroscopy (FTIR) describes local environment around TiO2 nanoparticles. Photoluminescence spectroscopy (PL) exhibits the change in PL intensity with phase change and different trends have been observed in emission edges.