Temperature dependence of the Cr3+-DOPED Mg2TiO4 near-infrared emission

This paper presents the Cr3+-activated Mg2TiO4 phosphor temperature dependance of its near infrared luminescence and its potential in the optical thermometry applications. In this respect, temperature dependences of three emission features were tested over the broad temperature range (10–500 K): (i) the luminescence intensity ratio (LIR) between emissions from 4T2→4A2 and 2E→4A2 transitions, (ii) the emission lifetime, and (iii) the shift of the 2E→4A2 emission band. We observed that LIR follows the Boltzmann equation for T > 300 K with the maximal value of relative sensitivity of 1.73 %K−1. The lifetime value of the 2E→4A2 transition strongly decreases with temperature with a maximal relative sensitivity of about 0.75 %K−1 at around 430K. Finally, the shift of the emission band is about 65 cm−1 over the complete temperature range. [Display omitted] •Synthesis of single phase Mg2TiO4:Cr3+ phosphor.•Multi readout approach to temperature sensing in first biological NIR window.•The maximum relative sensitivity of 1.73 %K−1 in the LIR mode at physiological temperatures.•The maximum relative sensitivity 0.75 %K−1 in the lifetime mode in broad temperature range from 100 K to 400 K.•Significant red shift of the Cr3+ R line with temperature increase.