This research mainly highlighted an intense deep red-emitting and Mn⁴⁺-powered oxyfluoride nanophosphor, Mg₁₄Ge_4.99O₁₆F₈:0.01Mn⁴⁺ (MGOF:Mn), which was synthesized via adopting a scalable synthesis route for commercial temperature sensing and artificial plant growth applications. The electron microscopic analysis confirmed the formation of nanosized particles without any defined shape or size distribution. The obtained nanophosphor exhibited sharp emission peaks at 659 nm and 631 nm under UV (317 nm) and blue excitation (417 nm) owing to Mn⁴⁺:²E_g → ⁴A_2g and Mn⁴⁺:²T_1g → ⁴A_2g transitions, respectively. The emission spectrum is situated in the deep red region of the CIE color diagram where the red color purity approached 100% under both the excitations. The absorption efficiency and the internal and external quantum efficiencies of this red-emitting system were calculated to be 53%, ∼77%, and ∼41%, respectively, under blue excitation of 417 nm, which indicated its potential for indoor plant cultivation. A prototype red LED was fabricated by pasting the red-emitting MGOF:Mn⁴⁺ nanophosphor powder on a 410 nm blue LED chip. The resulting electroluminescence spectrum overlapped with those of the important organic pigments of normal plants. Importantly, the thermometric properties of the nanophosphor were evaluated in detail for FIR and lifetime-based thermometry applications. The examined nanophosphor showed an extreme absolute sensitivity of 0.00326 K⁻¹ at 373 K with excellent reproducibility and temperature resolution. Because of the small particle size and high luminescence efficiency, the nanophosphor could be implemented in various nano-devices where non-contact optical thermometry is necessary for high performance.

中文翻译：

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专为植物生长和光学测温应用而开发的高效深红光发射 Mn4+ 驱动的氟氧化物纳米磷光体

这项研究主要突出了一种强烈的深红光发射和Mn ⁴⁺驱动的氟氧化物纳米磷光体，Mg ₁₄ Ge _4.99 O ₁₆ F ₈ :0.01Mn ⁴⁺ (MGOF:Mn)，它是通过采用商业温度下可扩展的合成路线合成的传感和人工植物生长应用。电子显微镜分析证实了纳米尺寸颗粒的形成，没有任何确定的形状或尺寸分布。由于Mn ⁴⁺ : ² E _g → ⁴ A _2g和 Mn ⁴⁺ : ² T _1g → ⁴ A ，所得纳米荧光粉在紫外（317 nm）和蓝色激发（417 nm）下在659 nm和631 nm处表现出尖锐的发射峰分别为_2g转换。发射光谱位于 CIE 色图的深红色区域，在两种激发下红色纯度均接近 100%。在417 nm蓝色激发下，该红光发射系统的吸收效率、内部和外部量子效率分别为53%、~77%和~41%，这表明其在室内植物栽培方面的潜力。通过将发红光的 MGOF:Mn ⁴⁺纳米磷光体粉末粘贴在 410 nm 蓝色 LED 芯片上，制造了原型红色 LED。由此产生的电致发光光谱与正常植物的重要有机色素的电致发光光谱重叠。重要的是，针对远红外和基于寿命的测温应用详细评估了纳米磷光体的测温特性。所检测的纳米磷光体在 373 K 时表现出 0.00326 K ^-1的极端绝对灵敏度，并具有出色的再现性和温度分辨率。由于粒径小和发光效率高，纳米磷光体可以应用于各种纳米器件中，其中非接触式光学测温对于高性能是必需的。