NaYF_4∶Yb^(3+),Er^(3+)上转换发光材料的葡聚糖表面改性及醛基化研究

Glucosan coated NaYF_4∶Yb^(3+),Er^(3+) up-conversion nanocrystal and its aldehyde modification

采用"两浴-溶剂热法"制备了NaYF_4∶Yb^(3+),Er^(3+)上转换发光纳米粒子(UCNP),利用葡萄糖在苷化温度下置换UCNP表面的油酸,制得表面包被葡聚糖的亲水性UCNP。进一步通过NaIO_4氧化表面葡聚糖,获得了醛基化UCNP。采用TEM及光纤光谱仪等对修饰前后材料的形貌、发光特性进行了表征。优化实验表明0.5mol/mL葡萄糖在130℃下包被葡聚糖48h效果最好,包被后的UCNP在水相中分散良好且可在超过2个月内保持原有发光强度的75%。通过调节NaIO_4用量及氧化反应时间可以调控表面醛基修饰量。

Up-conversion nanocrystals composite NaYF4∶Yb^3＋,Er^3＋（UCNP）was synthesized by＂two baths-solvo thermal＂method.Oleic acid on the surface of UCNP was replaced by hydrophilic glucosan under hydrothermal glycosidation temperature of glucose.The hydroxyl of glucosan was then converted to aldehyde group by NaIO4 oxidation.Morphology and fluoro luminescent properties of UCNPs were studied using TEM and fiber optic spectrometer.Coating temperature,concentration of glucose and incubation time were optimized at 130℃,0.5mol/mL and 48 h,respectively.The coated UCNP could be well dispersed in water and 75% of the original luminescence was maintained for more than 2months.It was also found that the amount of aldehyde group could be controlled by changing the concentration of NaIO4 and oxidation duration.This simple and reliable surface modification approach provided a new way to biological application of UCNP.