Kshetri Yuwaraj K, Regmi Chhabilal, Kim Hak-Soo, Lee Soo Wohn, Kim Tae-Ho
Research Center for Eco-Multifunctional Nano Materials, Sun moon University, Chungnam 31460, Republic of Korea.
Nanotechnology. 2018 May 18;29(20):204004. doi: 10.1088/1361-6528/aab2bf. Epub 2018 Feb 28.
Yb and Er doped YVO (Yb/Er:YVO) nanoparticles with highly efficient near-infrared to visible upconversion properties have been synthesized by microwave hydrothermal process. Uniform-sized Yb/Er:YVO nanoparticles were synthesized within 1 h at 140 °C which is relatively faster than the conventional hydrothermal process. Under 980 nm laser excitation, strong green and less strong red emissions are observed which are attributed to H, S to I and F to I transitions of Er respectively. The emission intensity is found to depend strongly on the concentration of Yb. The quadratic dependence of upconversion intensity on the excitation power indicates that the upconversion process is governed by two-photon absorption process.
通过微波水热法合成了具有高效近红外到可见光上转换特性的镱（Yb）和铒（Er）共掺杂的钒酸钇（Yb/Er:YVO）纳米颗粒。在140℃下1小时内合成了尺寸均匀的Yb/Er:YVO纳米颗粒，这比传统水热法相对更快。在980nm激光激发下，观察到强绿色发射和较弱的红色发射，它们分别归因于Er的从H、S到I以及从F到I的跃迁。发现发射强度强烈依赖于Yb的浓度。上转换强度对激发功率的二次依赖性表明上转换过程受双光子吸收过程支配。
