Crystal phase modified blue upconversion on Tm3+/Yb3+:BCZT ceramic phosphor benefits multifunctionality in white-light applications.
Dalton Trans
; 51(30): 11515-11525, 2022 Aug 02.
Article
em En
| MEDLINE
| ID: mdl-35838125
ABSTRACT
Rare earth (RE) doped perovskite oxide hosts especially titanates, are promising phosphor materials in terms of white-light emission owing to their extraordinary properties such as an exceptional hosting environment for RE-ions and a switchable crystal phase near the phase boundary. Here, we report a new strategy of crystal phase modification to enhance the blue upconversion (UC) efficiency to such an extent that the combinational mixing of blue and green/red-emitting phosphor gives intense white emission. The Lead free (Ba0.85Ca0.15)(Zr,Ti)O3 ceramics were synthesised at different sintering temperatures by incorporation of Tm3+/Yb3+ ions as dopants. The UC quantum efficiency of the Tm3+/Yb3+BCZT sample sintered at 1300 °C was recorded at different excitation power densities. It was observed that the crystal phase transformation from tetragonal to rhombohedral symmetry in the sample near the phase boundary plays a cruicial role in improving the quantum efficiency. White-light emission applications were demonstrated by preparing biphasic samples with powder mixing of a BCZTTm3+/Yb3+ (blue-emitting) + BCZTEr3+/Yb3+ (green/red-emitting) phosphor, and their composition were optimised at a mixed ratio. Thereafter, photometric characterization (CIE chromaticity, colour purity and corelated colour temperatures) was performed, and it indicated the suitability of the current biphasic samples in direct white-light (cooler) applications on an industrial scale. Crystal phase modified blue emission efficiency enhancement is a key feature of this work, which helps to generate approximately pure white-light with ideal chromacity (â¼0.333, 0.343) emission when Tm3+/Yb3+BCZT is mixed with a green emitting BCZTEr3+/Yb3+ phosphor.
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MEDLINE
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Ano de publicação:
2022
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Article