Development of a potential optical thermometric material through photoluminescence of Pr3+ in La2MgTiO6

In this work, we demonstrate a potential thermometric material after systematic studies on the concentration/temperature-dependent spectroscopic properties of Pr3+ excited multiplets and of the Pr3+-Ti4+ intervalence charge transfer (IVCT) state in (La1-xPrx)(2)MgTiO6. The experimental results indicate that the electron population efficiency between the involved Pr3+ 4f multiplets is directly governed by multi-phonon relaxation (MPR) and cross relaxation (CR), and the IVCT state provides an additional contribution to the D-1(2) luminescence. A schematic energy level diagram is proposed to illustrate the electron population pathway in Pr3+ doped La2MgTiO6. The observations clarify that the dramatic thermal-quenching of P-3(0) luminescence is mainly induced by the electronic configuration crossover between the P-3(0) multiplet and the IVCT state. On the other hand, the D-1(2) luminescence possesses an excellent thermal stability in a large temperature region. These temperature sensing features of the Pr3+ doped La2MgTiO6 material indicate its potential application in optical thermometric techniques.