Ratiometric optical thermometer with high sensitivity based on dual far-red emission of Cr3+ in Sr2MgAl22O36

A series of Cr3+ ions activated Sr2MgAl22O36 inorganic luminescence materials were successfully synthesized. The structure provides suitable crystal field for Cr3+ ions to achieve both broadband and narrowband emission simultaneously in far-red region. Cr3+ ions doped Sr2MgAl22O36 reach the maximum of luminescence intensity when the concentration is increased to 0.02. When the concentration exceeds the value, the luminescence intensity of Cr3+ ions is quenched by the dipole-dipole interaction. The fluorescence intensity ratio I-2/I-1 (I(1)and I-2 represent the intensity at 677 and 693 nm, respectively) originating from Cr3+ ions in Sr2MgAl22O36 shows good linearity in the Arrhenius plot. The relative sensitivity of Sr2MgAl22O36: Cr3+ material at 310 K (physiological temperature) reaches 1.7% which has good application potential on ratiometric thermometers. Present researches indicate that Sr2MgAl22O36: Cr3+ has great potential application value on ratiometric thermometers.