Structural, luminescence, and temperature sensing properties of the Er3+-doped germanate-tellurite glass by excitation at different wavelengths

Er3+-doped germanate-tellurite glasses were prepared by high-temperature melting method, in which structure, luminescent and, temperature-sensing properties were studied. The Raman spectrum indicates that the maximum phonon energy is low, which is 860 cm−1. The transmission spectrum indicates that the infrared transmissive range of glass is wide, visible, and infrared transmittance is high. Parameters of spectral line intensity Ωλ and radiation parameters were calculated based on Judd-Ofelt theory, which showed that the glass has large values of Ω2 and Ω6, and values of Ω2 and Ω6 decrease with increasing concentration of Er3+ ions. Strong up-conversion luminescence was obtained at 808, 980 and 1550 nmLD with wavelengths at 534, 553 and 668 nm, respectively, and strong down-conversion luminescence of 1.53 and 2.7 μm also were obtained. The up-conversion emission intensity under three-wavelength simultaneous excitation is significantly enhanced compared to monochromatic excitation. The emission intensity corresponding to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transition of Er3+ ions varied with temperature, and the fluorescence intensity ratio FIR of 556 nm and 524 nm increased with increasing temperature. In the temperature range from 330 to 610 K, the maximum sensitivity of glasses was 15.63 × 10−3 K−1 and 19.74 × 10−3 K−1 at T = 570 K, respectively under 808 and 980 nm LD excitation.