Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, c/ Sor Juana Inés de la Cruz, 3. Cantoblanco, E-28049 Madrid, Spain.
Nanotechnology. 2012 Dec 21;23(50):505205. doi: 10.1088/0957-4484/23/50/505205. Epub 2012 Nov 29.
Tetragonal zircon-type codoped Yb, Ln-GdVO(4) (Ln=Tm, Ho, Er) upconverting nanocrystals with square and rectangular sections were prepared through an efficient low-temperature hydrothermal synthesis. Further processing that combined annealing at 600 °C followed by coating of the surface with a uniform 5 nm-shell of SiO(2) resulted in a significant improvement of the intensity of the upconverted emitted visible light following near-infrared (~980 nm) diode laser excitation with respect to raw hydrothermal nanocrystals. Strong tunable color and bright visible light composed of red-green, blue and green emissions from Ho(3+), Tm(3+) and Er(3+), respectively, were generated by adjusting the Yb-Ln composition of these silica-coated nanocrystals. Based on calculations of CIE color coordinates, nearly ideal white upconversion light was achieved for samples of composition Gd(0.829)Yb(0.15)Tm(0.01)Ho(0.009)Er(0.002)VO(4).
四方锆石型共掺杂 Yb、Ln-GdVO(4)（Ln=Tm、Ho、Er）上转换纳米晶具有正方形和矩形截面，通过高效低温水热合成制备。进一步的处理包括在 600°C 下退火，然后用均匀的 5nm-SiO(2)壳层对表面进行涂层处理，与原始水热纳米晶相比，近红外（~980nm）二极管激光激发下上转换发射可见光的强度显著提高。通过调整这些涂覆有二氧化硅的纳米晶中 Yb-Ln 的组成，可以产生由 Ho(3+)、Tm(3+)和 Er(3+)分别发出的红-绿、蓝和绿可调谐颜色和明亮可见光。基于 CIE 颜色坐标的计算，对于组成 Gd(0.829)Yb(0.15)Tm(0.01)Ho(0.009)Er(0.002)VO(4)的样品，实现了近乎理想的上转换白光。
