Synthesis and spectroscopic analysis of Sm3+ doped CeO2 ceramic powders for the application of white LEDs
Journal
Ceramics International
Journal Volume
44
Journal Issue
15
Pages
18256-18263
Date Issued
2018
Author(s)
Abstract
Orange-red light-emitting Sm3+-doped cerium oxide (CeO2) ceramic powder with various concentrations of Sm3+ ions was prepared through a sol-gel process. X-ray diffraction and Rietveld analysis confirmed the formation of a purely cubic structure with a space group of Fm3?m. The lattice parameters and unit cell volumes of the CeO2:Sm3+ powder increased with the concentration of Sm3+ ions. The energy-dispersive X-ray spectra and corresponding mapping images confirmed the elemental composition and adequate dispersion of all elements in the CeO2:Sm3+ powder. A broad excitation band at approximately 365 nm was observed in the excitation spectra of CeO2:Sm3+ phosphors owing to the charge transfer transition from O 2p to Ce 4f orbitals. The Sm3+ doped CeO2 phosphors emitted sharp luminescence with a main peak at 615 nm under excitation at 360 nm. The spectral analysis revealed that the CeO2:Sm3+ phosphors exhibited strong orange-red emission. Concentration quenching was observed in the CeO2:Sm3+ phosphors with 0.5 mol% of critical concentration of Sm3+ ions due to dipole dipole interaction of two nearest Sm3+ ions. The quantum efficiency was observed as high as 58%. The thermal stability of the present materials was estimated with the evaluation of activation energy as 0.31 eV. The broad excitation band and sharp orange¡Vred emission indicated the potential use of CeO2:Sm3+ phosphors for white light-emitting diodes. ? 2018
Subjects
Fluorescence quenching
Orange-red emission
Quantum yield
Sol-gel
Thermal stability
White-light emitting diodes
SDGs
Type
journal article