Linzhao Ma,Guo Tian,Hongzhi Xiao,Longxiang Jiang,Qianbiao Du,Hao Li,Bin Yang
This research used the co-substitution strategy to prepare novel spinel-type Mg 3 Ga 2 SnO 8 ceramics sintered at 1430–1510 °C. Rietveld refinement and SEM showed that the Mg 3 Ga 2 SnO 8 ceramic had a cubic spinel structure with a space group of F d 3 ¯ m ( 227 ) , where Mg1 and Mg2/Ga1/Sn1 occupy the tetrahedron and octahedron, respectively. The relative density exhibited a considerable influence on the ε r of Mg 3 Ga 2 SnO 8 ceramics. In addition, the Q × f of the ceramics was closely related to the packing fraction and FWHM. Infrared reflection spectra were used to investigate the intrinsic dielectric characteristics of the ceramics. The P−V−L theory indicated that Sn−O and Ga−O bonds contribute substantially to the ε r and Q × f , respectively. The Mg 3 Ga 2 SnO 8 ceramics had the optimum microwave dielectric properties of ε r = 9.3, Q × f = 189,052 GHz, and τ f = −34.25 ppm/°C when sintered at 1470 °C. Therefore, Mg 3 Ga 2 SnO 8 ceramics exhibit a wide range of possible applications in the field of microwave media.
In recent years, rare earth ion and transition metal ion co-doped fluorescent materials have attracted a lot of attention in the fields of WLEDs and optical temperature sensing. In this study, I successfully prepared the dual-emission Mg3Ga2SnO8:Eu3+,Mn4+red phosphors and the XRD patterns and refinement results show that the prepared phosphors belong to the Fd-3m space group. The energy transfer process between Eu3+and Mn4+was systematically investigated by emission spectra and decay curves of Mg3Ga2SnO8:0.12Eu3+,yMn4+(0.002 ≤ y ≤ 0.012) phosphors and the maximum value of transfer efficiency can reach 71.2%. Due to the weak thermal quenching effect of Eu3+, its emission provides a stable reference for the rapid thermal quenching of the Mn4+emission peak, thereby achieving good temperature measurement performance. The relative thermometric sensitivities of the fluorescence intensity ratio and fluorescence lifetime methods reached a maximum value of 2.53% K−1at 448 K and a maximum value of 3.38% K−1at 473 K. In addition, the prepared WLEDs utilizing Mg3Ga2SnO8:0.12Eu3+phosphor have a high color rendering index of 82.5 and correlated color temperature of 6170 K. The electroluminescence spectrum of the synthesized red LED device by Mg3Ga2SnO8:0.009Mn4+phosphor highly overlaps with the absorption range of the phytochrome PFRand thus can effectively promote plant growth. Therefore, the Mg3Ga2SnO8:Eu3+,Mn4+phosphors have good application prospects in WLEDs, temperature sensing, and plant growth illumination.
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