Nanocrystalline scheelite SrWO4: a low temperature co-fired ceramic optical material-synthesis and properties

Nanocrystalline strontium tungstate (SrWO4) is synthesized through a single step modified combustion process. The X-ray diffraction, Fourier transform Raman and Infrared spectroscopy studies reveal that the as-prepared powder is single phase and possess tetragonal structure. The transmission electron microscopic investigations have shown that the particle size of the as prepared powder is in the range 18-22 nm. The optical constants are estimated from the UV-Visible studies and calculated optical band gap is 4.28 eV. The sample showed maximum transmission in the visible regions but poor transmittance in the ultraviolet region. The photoluminescence spectra recorded at different temperatures showed intense blue emission. The nanocrystalline SrWO4 obtained by the present combustion method was sintered to 95 % density at a relatively lower temperature of 810 A degrees C for 3 h. The dielectric constant (epsilon(r)) and loss factor (tan delta) of the sintered SrWO4 pellets at 5 MHz measured at room temperature were 9.9 and 6.29 x 10(-3) respectively. The experimental results obtained in this work demonstrate the application of SrWO4 as UV filters, transparent films for window layers on solar cells, anti-reflection coatings, scintillators, detectors and for low-temperature co-fired ceramic applications.