Li+ induced site occupation engineering in Bi3+ activated spinel-type phosphor for multiple optoelectronic applications

The utilization of phosphors for information storage, data encryption, temperature sensing, etc. has been becoming a research hotspot. However, modulating dynamic and pluralistic phosphor emissions is still a huge challenge. Herein, we developed a Li + -induced site occupation engineering in Bi 3+ activated Mg 2 SnO 4 (MSO) phosphor with multiple emissions and dynamic afterglow for versatile applications. Experiments and first-principles calculations demonstrated that Bi 3+ would simultaneously enter [MgO 4 ] tetrahedron and [SnO 6 ] octahedron to present red and blue emissions, respectively. As Li + ions were introduced into Mg 2 SnO 4 :Bi 3+ , the preferably generated [LiO 4 ] could hinder the Bi 3+ from entering [MgO 4 ] units, so as to force Bi 3+ to substitute Sn 4+ in [SnO 6 ], thereby leading to strengthened blue emission. Due to the distinct luminescence decay of Bi 3+ in tetrahedron and octahedron units, the luminescence colors were regulated from blue to purple and red with enhancing temperature upon UV light excitation, being suitable for luminescence intensity ratio (LIR) thermometer. Moreover, by virtue of the afterglow properties originating from the inherent oxygen vacancies of Mg 2 SnO 4 , the dynamic information encryption and anti-counterfeiting by Mg 2 SnO 4 :Bi 3+ , Li + were achieved. The proposed site occupation engineering can certainly spur several innovative ideas in manufacturing high-performance phosphors for versatile applications.