Synthesis and photoluminescence properties of Eu³⁺-doped ZrO₂ hollow spheres

Abstract

ZrO 2 :Eu 31 hollow spheres were successfully fabricated with the resin microspheres as the template. The sample characterizations were carried out by means of x-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence spectra. XRD results revealed that Eu 31 -doped samples were pure t-ZrO 2 phase after being calcined at 873 K. SEM results exhibited that this Eu 31 doped ZrO 2 was hollow spheres; the diameter and thickness of which were about 450 and 50 nm, respectively. Upon excitation at 394 nm, the orange-red emission bands at the wave length longer than 570 nm were from 5 D 0 ! 7 F J (J 5 1, 2) transitions. The asymmetry ratio of ( 5 D 0 ! 7 F 2 )/( 5 D 0 ! 7 F 1 ) intensity is about 1.61, 1.26, 1.42, 1.42, 1.40, and 1.38 for the Eu 31 concentration 0.4, 0.7, 1.0, 1.5, 2.0, and 2.5 mol%, respectively. These values suggest that the asymmetry ratio of Eu 31 ions is independent of the doping concentration. The optimal doping concentration of Eu 31 ions in ZrO 2 is 1.5 mol%. According to Dexter's theory, the critical distance between Eu 31 ions for energy transfer was determined to be 16 Å.

Phosphors with different morphology, formed under hydrothermal conditions on the basis of ZrO2:Eu3+ nanocrystallites

“…Precipitation methods [17], combustion [18], sol-gel technology [19], template synthesis [20], hydrothermal treatment [21], aerosol pyrolysis [22], anodizing [23] and impregnation [24] are used to obtain nanostructures of various morphology based on ZrO 2 doped with europium (III) ions. Among the above synthetic approaches, the hydrothermal method is the most universal, since it allows one to obtain nanomaterials with a narrow particle size distribution, high crystallinity, controlled by morphology and microstructure.…”

Preparation of efficient visible-light-driven BiOBr/Bi2O3 heterojunction composite with enhanced photocatalytic activities

“…As a promising environmental-friendly technology for wastewater remediation, semiconductor photocatalysis has attracted increasing attentions [1e6]. Among them, TiO 2 acted as a traditional photocatalyst has been obtained numerous experimental results during the forty decades since Fujishima and Honda discovered TiO 2 photochemical electrode in 1972 [7,8]. Although TiO 2 possesses excellent photocatalytic activity and stability, it could only response to UV light (ca.…”