In this study, deep-red emitting Mg 2 TiO 4 :Mn 4+ phosphor ceramics were synthesized by the high temperature solid-state reaction method. The ceramics can be excited by the 465 nm blue light and had a narrow emission with a full width at half maximum (FWMH) value of 31 nm. The peak wavelength was located at 658 nm, which matched the demanded wavelength for photosynthesis. The crystal field strength ( D q ) and the Racah parameters ( B and C ) were estimated by the Tanabe-Sugano diagram. The thermal conductivity of the Mg 2 Ti( 0.999 )O 4 :0.001Mn 4+ ceramic was 7.535 W/(m·K) at room temperature, which was one order of magnitude higher than that of the traditional packaging method using the silicone gel. A set of phosphor converted LEDs were fabricated by mounting the phosphor ceramics onto the 460 nm blue LED chips and the CIE coordinates can move from the blue region to the purple light region with the thickness of the ceramic increasing. These results indicated that the Mg 2 TiO 4 :Mn 4+ phosphor ceramic was suitable for plant lighting when combined with a blue LED chip.
Mg2TiO4:Mn4+(MTO:Mn4+) red phosphor has important applications in areas such as red LEDs and forensic science, but the preparation of MTO:Mn4+through the solid-state reaction method requires a high sintering temperature. Herein, MTO:Mn4+red phosphor was synthesized using the solid-state reaction method with LiCl flux, and its crystallographic structure and photoluminescence properties were studied to determine the influence of experimental parameters like the amount of fluxing agent added and sintering temperature in producing a bright red phosphor suitable for LEDs. The experimental results showed that samples with added LiCl could form pure MTO after sintering at 950 °C, whereas those without LiCl still contained a mixture of MTO and MgTiO3, even when sintered at 1400 °C. The optimal performance was achieved with a sample doped with 0.2 mol% Mn4+, synthesized using 50 wt% LiCl flux and sintered at 950 °C for 12 h. This sample exhibited a broad excitation band and a narrow red emission band peaking at 662 nm, confirming its excellent luminescence properties. Furthermore, a prototype red LED fabricated with a 377 nm chip and MTO:0.2% Mn4+phosphor achieved photoelectric conversion efficiency of 78.5% at a 100 mA drive current, confirming its viability for high-performance red LED manufacturing.
危险品化学品经营许可证（带存储）