Ultra-sensitive luminescence thermometry based on MgNb2O6:Dy3+/Pr3+ thermochromic phosphors

Luminescent materials have been explored for achieving highly sensitive and noncontact thermometry. Herein, a novel ratiometric luminescence thermometry strategy was proposed by combining the thermally induced redshift of the charge transfer band with the dramatic quenching of the intervalent charge transition in MgNb2O6 (MNO) phosphors doped with Dy3+ and Pr3+. The emission color of the resultant sample changes significantly from red to yellow as the temperature increases under single-beam irradiation, which is observable by the naked eye. Benefiting from the opposite thermal response of the luminescence of Dy3+ and Pr3+, the luminescence intensity ratio of Dy3+ and Pr3+ codoped MNO leads to excellent sensitivity. The maximum relative sensitivity and absolute sensitivity reached 7.61% K-1 at 300 K and 0.61 K-1 at 540 K, respectively. The investigated sample also exhibited excellent signal resolution, reversibility and temperature resolution. Consequently, Dy3+ and Pr3+ activated MNO phosphors are very promising in luminescence thermometry including visual temperature sensing and safety markers.