Due to the unique narrow-band red emission and broadband blue light excitation, as well as milder synthesis conditions, Mn⁴⁺ ion activated fluoride red phosphors show great promise for white light emitting diode (W-LED) applications. However, as the Mn⁴⁺ emission belongs to a spin-forbidden transition (²E_g → ⁴A₂), it is a fundamental challenge to synthesize these phosphors with a high external quantum efficiency (EQE) above 60%. Herein, a highly efficient and thermally stable red fluoride phosphor, Cs₂SiF₆:Mn⁴⁺, with a high internal quantum efficiency (IQE) of 89% and ultrahigh EQE of 71% is demonstrated. Furthermore, nearly 95% of the room-temperature IQE and EQE are maintained at 150 °C. The static and dynamic spectral measurements, as well as density functional theory (DFT) calculations, show that the excellent performance of Cs₂SiF₆:Mn⁴⁺ is due to the Mn⁴⁺ ions being evenly distributed in the host lattice Cs₂SiF₆. By employing Cs₂SiF₆:Mn⁴⁺ as a red light component, stable 10 W high-power warm W-LEDs with a luminous efficiency of ∼110 lm/W could be obtained. These findings indicate that red phosphor Cs₂SiF₆:Mn⁴⁺ may be a highly suitable candidate for fabricating high-performance high-power warm white LEDs.

中文翻译：

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高效且稳定的窄带红色荧光粉Cs ₂ SiF ₆：Mn ^4+，适用于高功率暖白光LED应用

由于独特的窄带红色发射和宽带蓝光激发以及较温和的合成条件，Mn ⁴⁺离子活化的氟化物红色磷光体在白光发光二极管（W-LED）应用中显示出了广阔的前景。但是，由于Mn ⁴⁺发射属于自旋禁止跃迁（² E _g → ⁴ A ₂），因此以高于60％的高外部量子效率（EQE）合成这些磷光体是一个根本性的挑战。在此，一种高效且热稳定的红色氟化物荧光粉Cs ₂ SiF ₆：Mn ⁴⁺被证明具有89％的高内部量子效率（IQE）和71％的超高EQE。此外，将近95％的室温IQE和EQE保持在150°C。静态和动态光谱测量以及密度泛函理论（DFT）计算表明，Cs ₂ SiF ₆：Mn ⁴⁺的出色性能是由于Mn ⁴⁺离子均匀分布在主晶格Cs ₂ SiF中₆。通过使用Cs ₂ SiF ₆：Mn ⁴⁺作为红光成分，可以获得稳定的10 W大功率暖色W-LED，其发光效率约为110 lm / W。这些发现表明红色荧光粉Cs₂ SiF ₆：Mn ⁴⁺可能是制造高性能大功率暖白色LED的高度合适的候选材料。