Sensitization of Mn²⁺ Luminescence by Eu²⁺: A Combined Study Using Optical Spectroscopy and Luminescence Dynamics...

Owing to the intriguing luminescent feature, Mn²⁺-doped materials have attracted a lot of attention. Unfortunately, their application potential is hampered by the parity-forbidden nature of Mn²⁺ 3d-3d transition, and the insufficient excitation light absorption is the main obstacle. Although the use of a sensitization strategy effectively addresses this issue, explicit knowledge of the sensitization mechanism is insufficient, severely limiting the improvement of Mn²⁺ luminescence performance in a wide range of materials. Herein, the sensitization of Mn²⁺ luminescence is investigated in Eu²⁺, Mn²⁺-codoped SrMgP₂O₇ which has the high luminescence efficiency upon UV excitation. The electronic transition properties of Eu²⁺ and Mn²⁺ are studied by VUV-UV-vis spectroscopy, and the sensitization mechanism is elucidated by luminescence dynamics simulations. Efforts are also made to evaluate the impact of temperature variation on the sensitization efficiency. Based on these discussions, the collaboration of high-efficiency Eu²⁺ → Mn²⁺ energy transfer via dipole-dipole interaction and suppression of Mn²⁺ luminescence loss results in the significant sensitization of Mn²⁺ luminescence in Eu²⁺, Mn²⁺-codoped materials, which are essentially associated with probable orbital hybridization and weak electron-vibration interaction, respectively. Current research provides a practical guideline for analyzing the luminescence sensitization effect in the donor-acceptor system, which facilitates the development of materials with unique optical features.