Concentration and temperature effect on luminescent properties of Nd${}^{3+}$-doped fluoroborophosphate glasses

Nd${}^{3+}$-doped fluoroborophosphate glasses of molar composition P${}_2$O${}_5$-B${}_2$O${}_3$-ZnO-BaF${}_2$-AlF${}_3$ were prepared by the conventional melt-quenching technique. The amorphous nature of the glass systems was identified based on the X-ray diffraction analysis. The Fourier transform infrared spectroscopy (FTIR) technique was used to explore the structure of these glasses. The optical properties of these glasses were investigated by mean of optical absorption and photoluminescence spectroscopy (PL). The temperature dependence of the fluorescence intensities ratio (FIR) for three thermally coupled pairs of levels (TCL) of Nd${}^{3+}$ ions were studied. It was found that the FIR measured for the different pairs of TCL increased exponentially with increasing temperature according to Boltzmann distribution law. By comparing our results with those reported in recent literature, we may suggest this glass system as good candidate for temperature sensing in a large temperature range going from 300 to 800 K with a good accuracy and maximum value for the thermal sensibility equal to 26 × 10${}^{-4}$ K${}^{-1}$ at 800 K.