钕有机框架配合物Nd(BTC)的双光子上转换荧光

稀土上转换荧光材料和金属有机框架配合物是材料学、化学等学科近年来的两大研究热点，引起了广泛的研究关注。其中，基于稀土元素Nd3+的配合物是目前较为普遍的上转换荧光材料。文章表征了通过溶剂热法合成的稀土有机框架配合物Nd(BTC)的吸收和荧光等光谱性能，发现在808 nm的激光激发下，Nd(BTC)的荧光峰位于1 064 nm左右；在580 nm的激光激发下，获得了位于450 nm左右的上转换荧光峰，其上转换发光机理可归结于激发态吸收和能量传递上转换。上述结果表明，该框架配合物可作为一种上转换发光材料，有望应用于生物荧光标记、荧光显示等多个领域。

Two-Photon Up-Conversion Fluorescence of a Neodymium Organic Framework Nd(BTC)

In the present work, a neodymium organic framework Nd(BTC) was synthesized by the solvothermal reaction of Nd(NO₃)₃·5H₂O and H₃BTC (BTC=1,3,5-benzenetricarboxylate) in mixed solvents of DMF, ethanol and water, and was identified by elemental analysis.This MOF complex was characterized using X-ray diffraction (XRD), thermogravimetry-differential scanning calorimetry (TGA-DSC) analysis, UV-visible absorption spectra and fluorescence spectra.This polycrystalline powder lost DMF and H₂O when heated to 120 ℃, then remained stable till the temperature reached 500 ℃.Near infrared fluorescence at 1064 nm due to the 4F3/2→4I_11/2 transition of Nd3+ ions was exhibited when excited by 808 nm laser beam.It was also been found that up-conversion fluorescence of Nd(BTC) peaked at about 450 nm due to 2D_5/2→4I_11/2 transition of Nd3+ ions can be observed under the excitation of a 580 nm laser line.The mechanism of the up-conversion fluorescence of Nd(BTC) at around 450 nm under the excitation of 580 nm laser can be ascribed to both excited-state absorption and energy transfer up-conversion.This result indicated that such MOF can be employed as an up-conversion luminescence material in many potential application areas such as bio-labeling and fluorescence image.