氟化钙荧光纳米晶的制备及在荧光打印中的应用

Preparation of Fluorescent Calcium Fluoride Nanocrystals and Their Application in Security Printing

基于柠檬酸钠辅助水热法,利用不同氟化原料成功合成了氟化钙纳米晶。产物通过X-射线粉末衍射、透射电子显微镜、动态光散射、紫外吸收光谱和荧光光谱等表征手段分析。结果表明氟化原料的差异不会对氟化钙的结晶状况,颗粒尺寸及颗粒形貌产生明显影响。氟化铵为原料制备的氟化钙纳米晶具有优异的胶体稳定性和显著的蓝色荧光性质。而氟化钠为原料制备的氟化钙纳米晶没有这些性质。该差异可能是由于在水热合成过程中,铵根离子的氮氢键引发氟化钙颗粒表面吸附的柠檬酸根离子上的羟基和羧基脱水缩合为碳点。由于这些性质,该氟化钙纳米晶可以应用到喷墨打印中进行隐形打印和信息的加密存储。

Calcium fluoride nanocrystals were successfully synthesized based on sodium citrate-assisted hydrothermal method using different fluorinated raw materials.The products were characterized by X-ray powder diffraction,transmission electron microscopy,dynamic light scattering,UV absorption spectroscopy and fluorescence spectroscopy.The results showed that the differences of fluorinated raw materials did not have significant effects on the crystallization status,particle size and particle morphology of calcium fluoride.The calcium fluoride nanocrystals prepared from ammonium fluoride had excellent colloidal stability and significant blue fluorescence properties.In contrast,the calcium fluoride nanocrystals prepared from sodium fluoride did not have these properties.The difference may be due to the nitrogen-hydrogen bonding of ammonium ions triggering the dehydration and condensation of hydroxyl and carboxyl groups on the citrate ions adsorbed on the surface of calcium fluoride particles to carbon dots during the hydrothermal synthesis.Due to these properties,the calcium fluoride nanocrystals can be applied to inkjet printing for invisible printing and encrypted storage of information.