Mg4InSbO8 Spinel: Double 2:1 Ordering in Tetrahedral and Octahedral Sublattices and Perspective Application as an Optical Thermometer via Mn2+/4+ Doping

• DOI: 10.1021/acs.chemmater.3c02008
• Publication Date: 2023-11-10T13:37:29Z
• Authors: Zien Cheng; Jinmei Huang; GuangXiang Lu; Yuhan Wu; Maxim Avdeev; Tao Yang; Pengfei Jiang
• Keywords: Ionic radius; Superstructure; Powder Diffraction

AB2O4-type spinel oxides were extensively investigated as prospective magnetic, photocatalytic, cathode, and host materials. Herein, a new Mg4InSbO8 was rationally designed structurally characterized by high-resolution X-ray powder diffraction (XRPD) in combination with neutron diffraction. crystallizes the Imma-superstructure lattice dimensions of = √2/2·aC, b 3√2/2·aC, c aC, where aC is parameter cubic (Fd3̅m) archetype spinel. The formation this hitherto unreported Imma-spinel superstructure result 2:1 Mg2+/Sb5+ ordering octahedral sublattice, which further creates two crystallographically independent tetrahedral sites distinctive sizes thereby resulting site-selective occupation for Mg2+ In3+ cations. first exhibiting double cationic both sublattices. Compared other ordered structures, we found that ionic radius charge differences, coordination geometry preference, chemical bonding character are all responsible unique doubly Mg4InSbO8. Theoretical calculations, together diffuse reflectance spectroscopy, revealed an indirect semiconductor. Moreover, multiple appropriate green- deep-red-emitting Mn2+ Mn4+ activators, respectively. Tunable color emission from green to white then deep red can be achieved Mg4InSbO8/Mn2+/4+ phosphors adjusting excitation energy. More importantly, activators experience thermal quenching responses, vivid change upon heating. highest sensitivity Sr 2.10% at 453 K, manifesting potential applications temperature sensing. Our findings pave way designing cation-ordered superstructures exploring expanding their applications.