General Nonaqueous Sol−Gel Synthesis of Nanostructured Sm₂O₃, Gd₂O₃, Dy₂O₃, and Gd₂O₃:Eu³⁺ Phosphor

Abstract

In this paper, we report on the synthesis of nanostructured rare earth oxides (Sm2O3, Gd2O3, Dy2O3) via a facile benzyl alcohol based nonaqueous sol−gel process followed by calcination at moderate temperature. During the synthesis, rare earth acetylacetonates were used as the precursors. The resulting samples were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and photoluminescent spectroscopy. The final nanostructured RE2O3 products were observed to possess two typical shapes: stacks of ultrathin nanodisks for Sm2O3 and hierarchical nanosheet microspheres for Gd2O3 and Dy2O3, respectively. This method could be extended to prepare high-quality luminescent Gd2O3:Eu3+ flowerlike superstructures with a strong red emission corresponding to 5D0 → 7F2 transition (612 nm) of Eu3+ under ultraviolet excitation (260 nm). The possible formation mechanisms of the ultrathin nanodisk stacks and hierarchical nanosheet microspheres are proposed on the basis of the characterization results. This study provides an alternative nonaqueous approach for the synthesis of nanostructured rare earth oxides.

Novel Gd(OH)3, GdOOH and Gd2O3 Nanorods: Microwave-Assisted Hydrothermal Synthesis and Optical Properties

“…Nowadays, rare earth hydroxide/oxide nanomaterials have received special attention because of their excellent physical and chemical properties, which provide a wide variety of applications in the nanotechnology field [1][2][3][4][5][6] . Among various types of rare earth hydroxide/oxide materials, gadolinium hydroxide (Gd(OH) 3 ), gadolinium oxyhydroxide (GdOOH) and gadolinium oxide (Gd 2 O 3 ) exhibit important functional properties that depend on the structure.…”

“…Gadolinium oxyhydroxide is a stable phase obtained by the thermal dehydration of gadolinium hydroxide and has a simple layered structure. So, these materials have been investigated as promising candidates in the field of high throughput luminescent devices, catalysis and other functional devices based on their excellent electronic, optical and physicochemical responses arising from 4f electrons [5][6][7] .…”

“…Some methods are reported in the literature to obtain well defined Gd(OH) 3 , GdOOH and Gd 2 O 3 nanostructures such as electrochemical route, microwave, sol-gel synthesis, combustion, solid state reaction, and polyol method [3][4][5][6][7][8] . However, most of these methods require long processing times due to slow reaction kinetics.…”

Photoluminescence properties of gadolinium oxide nanophosphor

“…The photoluminescence (PL) excitation and emission spectrum were recorded with a Shimadzu Spectroflourimeter equipped with Xe lamp as an excitation source at room temperature. [2]. No crystalline impurity apart from rare earth oxides can be determined from the PXRD analysis.…”

“…Different synthetic routes have been reported in literatures for the preparation of oxide nanoparticles such as sol-gel, hydrothermal, combustion, co-precipitation etc [2,3]. The energy consuming solid-state reaction method could not produce desirable RE 2 O 3 .…”