Synthesis of Uniform Rare Earth Fluoride (NaMF₄) Nanotubes by In Situ Ion Exchange from Their Hydroxide [M(OH)₃] Parents

Abstract

In this article, we demonstrate the production of uniform hexagonal sodium rare earth fluoride (beta-NaMF(4)) nanotubes through a hydrothermal in situ ion-exchange reaction by using rare earth hydroxides [M(OH)(3)] as a parent. The trivalent rare earth hydroxides were hydrothermally prepared at 120 degrees C and possessed a quasi-layered structure, which could be formed to be nanotubal morphology through a rolling up process from 2-D sheets. Moreover, the hexagonal structure of rare earth hydroxides [M(OH)(3)] displays a noticeable similarity with beta-NaMF(4). This similarity makes the formation of beta-NaMF(4) with nonlayered structure possible through in situ chemical transformation from M(OH)(3) with a layered structure. The single-crystal beta-NaMF(4) nanotubes were synthesized with well-controlled diameter (80-500 nm), aspect ratio (6-30), wall thickness (25-80 nm), and contents (such as M = Pr, Sm, Gd, Tb, Dy, Er, as well as lanthanide-doped rare earth NaMF(4)). The multicolor upconversion fluorescence has also been successfully realized in the Yb(3+)/Er(3+) (green) and Yb(3+)/Tm(3+) (blue) co-doped beta-NaMF(4) nanotubes by UC excitation in the NIR region. The various UC emission ratios of the samples were investigated as a function of hydrothermal reaction time to research the UC properties of the products and to further demonstrate the hydrothermal in situ ion-exchange process.

Fabrication of ordered magnetite-doped rare earth fluoride nanotube arrays by nanocrystal self-assembly

“…However, there have been few reports of the preparation by nanocrystal selfassembly of the type of well defined and ordered oriented 1-D nanotubes,which are much desired for nano-electronic and biological applications. Such nanotubes are different from the single-crystal nanotubes we have previously reported [14,25], because they can potentially be fabricated by selfassembly of different kinds of nanocrystals,allowing the functional properties of the nanotubes to be tailored according to the target application; as a result,multifunctional nanotubes and nanotube arrays can be obtained.…”

Rare earth based nanostructured materials: synthesis, functionalization, properties and bioimaging and biosensing applications

“…Firstly, RE(OH) 3 nanotubes of dimensions of 300 × 50 nm were synthesized after submitting at 120°C an aqueous solution of the corresponding RE nitrates at pH 14. Such RE(OH) 3 nanotubes were then treated at 120°C with aqueous solutions containing HF and NaF to obtain NaREF 4 nanotubes [101]. CePO 4 nanotubes were also prepared without additives after hydrothermal reaction of Ce(NO 3 ) 3 [104].…”

Nanopartikel für die Aufwärtskonversion

“…[453][454][455][456][457][458] UC-Leuchtstoffe auf Basis von makro-, mikro oder submikrokristallinem NaYF 4 wurden detailliert erforscht, und die Resultate finden sich zusammengefasst in mehreren Veröffentlichungen. [33,34,50,[375][376][377][378] -dotierte LiYF 4 -Nanokristalle waren Gegenstand einer Veröf-fentlichung von Yan et al [381] In makrokristallinem LiYF 4 :Nd 3+ wurde der Lawineneffekt -der seinerseits wiederum zu UC führen kann [382,383] -bei Temperaturen unter 60 K beobachtet. [ [385][386][387] Meijerink et al [388] 4 , das Photonenkaskadenemission (Zweiphotonenemission, "quantum cutting") im sichtbaren Spektralbereich zeigt.…”