Reversible luminescence of Bi3+ ions by X-ray induced crystal field regulation

Variations in the crystal field of optical crystal materials directly influence the energy level transitions and non-radiative relaxation processes of doped ions, resulting in changes to luminescence properties. However, current crystal field regulation strategies, such as matrix component regulation and ion doping, fail to achieve reversible control. This study introduces a control strategy for the crystal field using X-ray irradiation, enabling repeated adjustments of the Cs2KGdF6 crystal field, demonstrating excellent memory retention and cyclic stability. By modifying the crystal field environment of Cs2KGdF6, the emergence and quenching of Bi3+ photoluminescence can be precisely controlled. This reversible, irradiance-induced crystal field change phenomenon holds promising applications in X-ray imaging and radiation dose monitoring. This study also presents a strategy for managing crystal field changes.