A ratiometric optical thermometer with tunable sensitivity and superior signal discriminability based on Eu2+/Eu3+ co-doped La1-yGdyAlO3 phosphors

The La1-0.03-yGdyAlO3: 0.03Eu (y = 0.2-0.8) phosphors are prepared via solid phase method. The normal thermal quenching of Eu2+ ion and abnormal thermal quenching of Eu3+ ion in La1-0.03-yGdyAlO3: 0.03Eu (y = 0.2-0.8) phosphors are explained by the configuration coordinate system and energy transfer process. Considering the fluorescence intensity ratio temperature measurement technology, the temperature sensitivity values of the phosphors increase with the increase of Gd3+ ion concentration. When Gd3+ ion concentration is 0.8, the maximal S-a and S-r can even reach 0.084 K-1 and 3.233% K-1. Moreover, the excellent separation of emission peaks of Eu2+ and Eu3+ ions also provides good signal discriminability for temperature measurement. These results indicate that the La1-0.03-yGdyAlO3: 0.03Eu phosphors can be used as the superior non-contact optical thermometry materials.