Energy-Splitting Emission from Cr-Pr-Doped Mgga2o4 Persistent Luminescence Nanoparticles for Ratiometric Temperature Sensing

Abstract

The spinel structure MgGa2O4 (MGO) exhibits abundance defects, achieving the modulation of emission by ions doping as persistent luminescence nanoparticles (PLNPs). Here, we introduced Cr ions into MGO to achieve near-infrared (NIR) emission, and Pr ions to tune the lattice environment to enhance NIR emission. The optimal composite, as MgGa2O4: 0.005Cr, 0.003Pr (MGCP), achieved the enhanced NIR emission at 709 nm under 222 nm excitation. The concentration quenching was observed due to electric dipole-quadrupole interaction at high Cr and Pr content for MGCP, while afterglow mechanism was revealed as the energy transfer occurs from the host to Cr ions. We observed the emission at 709 nm decreased with increasing temperature, while the satellite signal at 650 nm was observed with increased first and then decreased intensity as the energy-splitting emission of Cr ions at 303-528 K. Ratiometric temperature sensing was therefore realized with the luminescence intensity ratio at 709 and 650 nm under excitation at 222 nm. The thermal quenching was discussed with the thermally coupled energy level for the temperature sensing. Thus, the energy-splitting emission of Cr ions is confirmed with the ratiometric temperature sensing.

Keywords: energy-splitting, Persistent Luminescence Nanoparticles, Ratiometric temperature sensing