Full color white light, temperature self‐monitor, and thermochromatic effect of Cu+ and Tm3+ codoped germanate glasses

Abstract

AbstractLighting sources with full‐color visible output are widely preferred in practical applications. In addition, modern lighting sources also tend to be intelligentized, and the intelligentization asks for smart luminescence materials. In this work, we attempt to develop novel full‐color emitting material with temperature sensing and thermochromatic ability. To this end, the Cu2+ is successfully reduced to Cu+ which is incorporated into the germanate glasses. The glasses are prepared via a melt‐quenching technique using graphite powders as reducing reagent. The supper‐broadening of the excitation and the emission spectra of Cu+ in the germanate glasses are observed. Full‐color emission is realized by introducing Tm3+ as co‐dopant to provide the blue component in the spectra. The energy transfer behavior between Cu+ and Tm3+ is investigated, and it is found that these two luminescence centers are independently existent without energy transfer between them. The chromatic properties of the Cu+/Tm3+ co‐doped glasses are tuned by Tm3+ concentration and excitation wavelength. The temperature sensing based on the fluorescence intensity ratio technique is demonstrated, and a constant sensitivity for the temperature detection is obtained. Moreover the thermochromatic property is also investigated, and it is found that the studied Cu+/Tm3+‐doped glasses exhibit excellent thermochromatic performance.