The Effect of Particle Morphology and Crystallite Size on the Upconversion Luminescence Properties of Erbium and Ytterbium Co-doped Yttrium Oxide Phosphors

Abstract

Phosphor particles (ca. 60 nm in size) of yttrium oxide co-doped with Er 3+ and Yb 3+ ions were prepared by a precipitation method in the presence of EDTA. Their physical properties were compared to much larger particles (ca. 600-800 nm in size) prepared in the absence of EDTA. All of the particles were shown to have crystallized in the cubic phase, and all exhibited blue, blue-green, and green-yellow upconversion emission when excited with laser light of wavelength equal to 632.8 nm. These upconversion emissions were shown to be excited by a two-photon process. The most intense yellow-green upconversion emission occurs when the crystallite size is between 75 and 200 nm and the particle size is 600 to 800 nm. Cross-relaxation processes between Er 3+ ions are suggested to be responsible for the more efficient upconversion in the larger particles. There is evidence from spectra taken in the temperature range 30 to -190°C that there are two different hot bands in the given region of the spectrum. These two emission manifolds are explained as arising from the two different Er 3+ lattice sites in the cubic Y 2 O 3 :Er 3+ structure. When using red excitation (rather than infrared excitation), the presence of Yb 3+ was found to be detrimental, as it diminished the upconversion intensity.

Synthetic versatility of nanoparticles: A new, rapid, one-pot, single-step synthetic approach to spherical mesoporous (metal) oxide nanoparticles using supercritical alcohols

“…Two emission bands were also observed near 550 and 680 nm in the PL spectra of the NPs (Figs. 21d and e), and the intensity of the red emission was greater than that in the green region due to the efficient energy transfer from the Yb co-dopant to the Er luminescence center [81]. These results confirmed that Yb co-doped CeO 2 :Er MARIMO NPs with efficient UC emission were successfully prepared via the one-pot, single-step reaction in scMeOH.…”

“…Next, to further explore the versatility of the one-pot, one-step synthetic procedure, the preparation of Er, Yb co-doped nanoparticles was attempted [81]. Yb co-doped CeO 2 :Er MARIMO NPs, CeO 2 :Er,Yb (100:1:1), were [79] (Figs.…”

Cathodoluminescence of Powder Layers of Nanometer-Sized Y2O3:Eu and Micrometer-Sized ZnO:Zn Phosphor Particles

“…where W is the coating weight, ρ is the density of crystalline phosphor material, 5.6 g/cm 3 for ZnO:Zn and 5.0 g/cm 3 for Y 2 O 3 :Eu, and B is the packing density in the layer. An attempt to determine the packing density from SEM pictures recorded at high-tilt angles yielded R207 an estimated value of about 70%.…”

“…[1][2][3][4][5] More recently we have given an account on a CL study on double layers of zinc doped zinc oxide (ZnO:Zn) and nanometer sized (NS) europium doped yttrium oxide particles (Y 2 O 3 :Eu). 6 The objective of that study was to increase the light output of phosphor layers by making double layers of low and high voltage phosphors.…”

Structural, morphological and luminescence properties of nanocrystalline up-converting Y1.89Yb0.1Er0.01O3 phosphor particles synthesized through aerosol route

“…In recent years, there is a great interest in the investigation of up-conversion luminescence materials due to the wide range of their applications, such as in solid state lasers, screen displays, sensors, optical data storage, fluorescent labels for sensitive detection of bio-molecules and telecommunications [2][3][4][5][6]. The most commonly used activator is trivalent rare earth ion Er 3+ since it posses the metastable 4 I 9/2 and 4 I 11/2 levels that can be filled using the low-cost high-power diode laser of 980 nm.…”