Upconversion based temperature sensing ability of Er3+-Yb3+ codoped SrWO4: An optical heating phosphor

The present paper covers a detail explanation about the laser induced optical heating and temperature sensing ability of intense green upconversion emitting Er3+-Yb3+ codoped SrWO4 phosphor. The structural studies based on X-ray diffraction and Fourier transform infrared analysis confirmed the phase formation, crystallinity and the presence of vibrational bands of the corresponding host lattice. The optical investigation was performed by recording the diffuse reflectance and upconversion emission spectra upon a 980 nm excitation. Multiphoton upconversion processes were confirmed by pump power dependence study for the various emission bands throughout the visible region. Optical thermometry has been performed using the fluorescence intensity ratio technique in which two thermally coupled levels of the green emission bands were used. A relatively low temperature (518 K) sensor with very high sensor sensitivity (14.98 x 10(-3) K-1) is determined from the observed results. The optical heating ability of the synthesized phosphor is also determined by using the results of the optical thermometry and found the heat generation up to similar to 417 K. The results obtained may possibly be used in cancer therapy. (C) 2014 Elsevier B.V. All rights reserved.