Abstract Fluorescent photonic crystal films (PCFs), which consisted of monodisperse NaYF4:10Yb, 0.5Tm@SiO2 or NaYF4:10Yb, 0.5Er, 0.2Tm@SiO2 core-shell spheres (10%, 0.5% and 0.2% represent the reactant mole percentage), were successfully fabricated. The morphologies and structures of PCFs were measured, while the fluorescent properties of NaYF4 in PCFs with different photonic band gap (PBG) positions were investigated. Besides, the energy transfer process in thermal coupled energy levels of NaYF4:10Yb, 0.5Tm@SiO2 under different temperatures was discussed. The results indicated that the short wave emission of NaYF4 can be enhanced by the regulation of photon mode density (PMD) in photonic crystals. Particularly, when the infrared 800 nm emission peak was in the range of PBG position of the PCF sample, the energy transfer process of 3H4-3H6 was suppressed and the short wave emission was enhanced by 1.64 times. Due to the well thermal radiation ability of silica shell, the thermal coupled energy levels (3F3 and 3H4) of NaYF4:10Yb, 0.5Tm@SiO2 core-shell spheres exhibited more stable emission intensities than NaYF4:10Yb, 0.5Tm nanoparticles, when the experimental temperatures varied from 30 to 300 °C.

中文翻译：

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提高 NaYF 4 @SiO 2 光子晶体薄膜的上转换效率和热稳定性

摘要 荧光光子晶体薄膜 (PCFs)，由单分散 NaYF4:10Yb、0.5Tm@SiO2 或 NaYF4:10Yb、0.5Er、0.2Tm@SiO2 核壳球组成（10%、0.5% 和 0.2% 代表反应物摩尔数）百分比），成功制造。测量了 PCF 的形态和结构，同时研究了 NaYF4 在具有不同光子带隙 (PBG) 位置的 PCF 中的荧光特性。此外，还讨论了NaYF4:10Yb、0.5Tm@SiO2在不同温度下热耦合能级的能量传递过程。结果表明，通过调节光子晶体中的光子模式密度（PMD）可以增强 NaYF4 的短波发射。特别是当红外 800 nm 发射峰在 PCF 样品的 PBG 位置范围内时，3H4-3H6的能量转移过程受到抑制，短波发射增强1.64倍。由于二氧化硅壳良好的热辐射能力，NaYF4:10Yb、0.5Tm@SiO2核壳球的热耦合能级（3F3和3H4）比NaYF4:10Yb、0.5Tm纳米粒子表现出更稳定的发射强度，当实验温度从 30 到 300 °C 不等。