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

The La 1-0.03- y Gd y AlO 3 : 0.03Eu ( y  = 0.2–0.8) phosphors are prepared via solid phase method. The normal thermal quenching of Eu 2+ ion and abnormal thermal quenching of Eu 3+ ion in La 1-0.03- y Gd y AlO 3 : 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 Gd 3+ ion concentration . When Gd 3+ 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 Eu 2+ and Eu 3+ ions also provides good signal discriminability for temperature measurement. These results indicate that the La 1-0.03- y Gd y AlO 3 : 0.03Eu phosphors can be used as the superior non-contact optical thermometry materials.