Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, Manipal, Karnataka-576104, India.
Materials Engineering, Indian Institute of Technology Gandhinagar, Gujarat-382355, India.
Methods Appl Fluoresc. 2022 Mar 9;10(2). doi: 10.1088/2050-6120/ac58e6.
Anisotropic rare earth ion (RE) doped fluoride upconversion particles are emerging as potential candidate in diverse areas, ranging from biomedical imaging to photonics. Here, we develop a facile strategy to synthesize NaYF: Yb, Gd, Er, and NaYF: Yb, Gd, Tm upconversion nanorods via microwave synthesis route by controlling the synthesis time and compared the optical properties similar nanorods prepared via solvothermal technique. With the increase in synthesis time, the phase of the particle found to change from mixed phase to purely hexagonal and morphology of the particles change mixed phase of spherical and rod-shaped particles to completely nanorods for a synthesis time of 60 min. Further, the intrinsically hydrophobic particles changed to hydrophilic by removal of oleic capping via acid treatment and the amine functionalized silica coating. The upconversion luminescence as well as laser power dependent emission properties of the surface modified particles elucidate that surface modification route influence the upconversion luminescence as well as solvent dependent emission properties. Moreover, the laser power dependent studies elucidate that the upconversion process in a multi-photon process.
各向异性的稀土离子（RE）掺杂氟化物上转换粒子在从生物医学成像到光子学等多个领域中作为潜在的候选材料而崭露头角。在这里，我们通过微波合成路线开发了一种简便的方法来合成 NaYF:Yb、Gd、Er 和 NaYF:Yb、Gd、Tm 上转换纳米棒，通过控制合成时间，并与通过溶剂热技术制备的具有相似光学性质的纳米棒进行了比较。随着合成时间的增加，发现颗粒的相从混合相转变为纯六方相，颗粒的形态从混合相的球形和棒状颗粒转变为完全的纳米棒，合成时间为 60 分钟。此外，通过酸处理去除油酸封端，将固有疏水性的颗粒转变为亲水性颗粒，并用胺官能化的硅烷进行涂层。表面修饰颗粒的上转换发光和激光功率依赖的发射特性表明，表面修饰路线会影响上转换发光以及溶剂依赖的发射特性。此外，激光功率依赖的研究表明，上转换过程是一个多光子过程。
