Cr³⁺-activated phosphors with high quantum efficiency show excellent promise in the field of near-infrared (NIR) phosphor converted light-emitting diodes (pc-LEDs). Here, we design an annealing program for Cr³⁺-doped phosphors containing variable valence elements that cannot be prepared in a reducing atmosphere to enhance their luminescence efficiency and thermal stability. A novel phosphor, Li₂Mg₃SnO₆:Cr³⁺, developed by this annealing design, containing variable valence element Sn, exhibits higher quantum efficiency and better thermal stability than the one prepared by the conventional solid-state reaction. The Li₂Mg₃SnO₆:0.03Cr³⁺ sample exhibits broadband NIR emission with a full width at half-maximum (FWHM) of 201 nm. After annealing, the internal quantum efficiency (IQE) and external quantum efficiency (EQE) of the Li₂Mg₃SnO₆:0.03Cr³⁺ sample are enhanced from 48.5% to 84.7% and from 22.7% to 32.6%, respectively, and the thermal quenching temperature at which the luminescence intensity of the phosphor reduces to half of its initial value is promoted from ∼400 K to ∼425 K. The luminescence intensity of the optimized Li₂Mg₃SnO₆:0.03Cr³⁺ sample at 425 K (∼152 °C) remains 49.2% of its initial intensity at 300 K. A NIR pc-LED is fabricated by combining the optimized Li₂Mg₃SnO₆:0.03Cr³⁺ sample with a blue LED (455 nm blue chip), and the NIR radiant fluxes of 3.676 mW (at 10 mA) and 29.21 mW (at 100 mA), as well as a maximum NIR photoelectric efficiency of 14.2%, are obtained. The results show that this novel phosphor has great application potential in NIR pc-LEDs, and the annealing design exhibits huge potential for improving the optical properties of Cr³⁺-activated phosphors.

中文翻译：

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应用于近红外发光二极管的宽带近红外Cr3+掺杂荧光粉：通过退火增强发光和热稳定性

具有高量子效率的Cr ³⁺激活荧光粉在近红外（NIR）荧光粉转换发光二极管（pc-LED）领域显示出良好的前景。在这里，我们为无法在还原气氛中制备的含有变价元素的Cr ³⁺掺杂荧光粉设计了退火程序，以提高其发光效率和热稳定性。通过这种退火设计开发出一种含有变价元素Sn的新型荧光粉Li 2 Mg 3 SnO 6 : _Cr 3+ _，与_传统固^{相反应制备的荧光粉相比，具有更高的量子效率和更好的热稳定性。}Li ₂ Mg ₃ SnO₆ :0.03Cr ³⁺样品表现出宽带近红外发射，半峰全宽 (FWHM) 为 201 nm。_{退火后，Li 2} Mg ₃ SnO ₆ :0.03Cr ³⁺样品的内量子效率（IQE）和外量子效率（EQE）分别从48.5%提高到84.7%和22.7%提高到32.6%，荧光粉发光强度降至初始值一半时的热猝灭温度从~400 K提升至~425 K。优化后的Li 2 _Mg 3 _SnO 6 _: 0.03Cr ^{3+的发光强度}425 K (∼152 °C) 下的样品仍保持其 300 K 时初始强度的 49.2%。通过将优化的 Li 2 Mg 3 _SnO 6 _: 0.03Cr ₃₊样品^与蓝色 LED (455 nm蓝色芯片），获得了3.676 mW（10 mA时）和29.21 mW（100 mA时）的NIR辐射通量，以及最大NIR光电效率14.2%。^{结果表明，这种新型荧光粉在近红外pc-LED中具有巨大的应用潜力，并且退火设计对于改善Cr 3+}激活荧光粉的光学性能具有巨大的潜力。