Correlating Local Compositions and Structures with the Macroscopic Optical Properties of Ce3+-Doped CaSc2O4, an Efficient Green-Emitting Phosphor - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Chemistry of Materials Année : 2017

Correlating Local Compositions and Structures with the Macroscopic Optical Properties of Ce3+-Doped CaSc2O4, an Efficient Green-Emitting Phosphor

Résumé

Calcium scandate (CaSc2O4) substituted with small amounts (<1%) of Ce3+ is a recently discovered bright-green-emitting phosphor with favorable light absorption and emission properties and robust temperature stability that make it well suited for solid-state white-lighting applications. Combined analyses of scattering, solid-state nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), and photoluminescence measurements establish the compositional and structural origins of the macroscopic optical properties of this phosphor material. Simultaneous refinements of synchrotron X-ray and neutron diffraction data of Ce3+-doped CaSc2O4 enable the average crystal structure to be determined, which is shown to correspond to an exceedingly rigid host structure, as corroborated by density functional theory (DFT) calculations. Such structural rigidity leads to high quantum efficiency, which is optimized by the substitution of as little as 0.5 mol % of Ce3+ for Ca2+ ions, with higher extents of Ce3+ substitution leading to decreased photoluminescent quantum yields. Solid-state Ca-43 and Sc-45 magic-angle spinning (MAS) NMR spectra are sensitive to the effects of the paramagnetic Ce3+ dopant ions on nearby atoms in the host structure and yield evidence for local structural distortions. EPR measurements provide direct insights on structures of the Ce3+ ions, as a function of Ce3+ substitution. The combined scattering and spectroscopic analyses yield detailed new understanding of the local and long-range structures of Ce3+-doped CaSc2O4, which account for the sensitive composition-dependent optical properties of this important phosphor material.

Dates et versions

hal-01539898 , version 1 (15-06-2017)

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Citer

Nathan C. George, Jakoah Brgoch, Andrew J. Pell, Clayton Cozzan, Adam Jaffe, et al.. Correlating Local Compositions and Structures with the Macroscopic Optical Properties of Ce3+-Doped CaSc2O4, an Efficient Green-Emitting Phosphor . Chemistry of Materials, 2017, 29 (8), pp.3538-3546. ⟨10.1021/acs.chemmater.6b05394⟩. ⟨hal-01539898⟩
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