Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas 78249, USA.
Nanoscale. 2014;6(3):1667-74. doi: 10.1039/c3nr03317a.
There is increasing interest in rare earth (RE) doped nanoparticles (NPs) due to their sharp absorption and photoluminescence (PL) in the near infrared (NIR) spectral region. These NIR based nanoparticles (NPs) could allow biological imaging at substantial depths with enhanced contrast and high spatial resolution due to the absence of auto fluorescence in biological samples under infrared excitation. Here, we present the highly efficient infrared photoluminescence in GdF₃:Nd(3+) nanoparticles under 800 nm excitation within the hydrodynamic size limitations for bio-applications. The downconversion (Stokes emission) absolute quantum yields (QY) in powder, polymaleic anhydride-alt-1-octadicene (PMAO) coated powder and colloidal solutions have been investigated. QY measurements have revealed that downconversion (Stokes emission) QYs of approximately 5 ± 2 nm sized GdF₃:1% Nd(3+) colloidal NPs are 2000 times higher than those of efficient upconversion (UC) particles NaYF₄:20% Er/2% Yb of the same size. Furthermore, the utility of these NIR emitting nanoparticles for bioimaging probes has been demonstrated by confocal imaging and spectroscopic study.
由于在近红外（NIR）光谱区域具有尖锐的吸收和光致发光（PL）特性，人们对稀土（RE）掺杂纳米粒子（NPs）的兴趣日益增加。这些基于近红外的纳米粒子（NPs）可以在生物样品中不存在自发荧光的情况下，通过红外激发实现高对比度和高空间分辨率的生物成像，因为它们在近红外区域有吸收。在这里，我们展示了在 800nm 激发下，在水动力尺寸限制范围内，GdF₃：Nd（3+）纳米粒子具有高效的红外光致发光性能。我们研究了粉末、聚顺丁烯二酸酐-alt-1-辛烯（PMAO）涂覆的粉末和胶体溶液中 GdF₃：1%Nd（3+）胶体 NPs 的下转换（Stokes 发射）绝对量子产率（QY）。QY 测量表明，约 5±2nm 尺寸的 GdF₃：1%Nd（3+）胶体 NPs 的下转换（Stokes 发射）QY 比相同尺寸的高效上转换（UC）粒子 NaYF₄：20%Er/2%Yb 高 2000 倍。此外，通过共聚焦成像和光谱研究，还证明了这些近红外发光纳米粒子在生物成像探针中的应用。
