Eu3+-activated SrY2O4:Ce4+/3+red-phosphor for WLEDs: Structural and luminescent insights from experimental and theoretical approaches

Autor(es)

Saraiva, Leonardo F. ; Bispo-Jr, Airton G. ; Lima, Sergio A. M. ; Pires, Ana M.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Alloys and Compounds; v. 938, p. 11-pg., 2022-12-29.

Resumo

Herein, single-phase Eu3+-activated SrY2O4:Ce4+/3+ red-emitting phosphor was produced by an adapted Pechini route under softer synthesis conditions (1100 degrees C in CO reducing atmosphere) compared to those reported so far. A detailed structural study conducted by Rietveld refinement and DFT calculations confirmed the presence of two hexa-coordinated Y3+ sites that are occupied by Eu3+. Cerium is present in a mixed oxidation state, where the proportion of Ce4+/Ce3+ was determined as 70/30% by X-ray photoelectron spectroscopy (XPS), and this influences the SrY2O4 phase stabilization by increasing the point defect concentration. A thorough analysis of the photoluminescent features of Eu3+-activated phosphor revealed its occupancy in at least two non-equivalent local sites belonging to the C1 point group. Furthermore, the excited state dynamics of the phosphors were enlightened by the theoretical band structure determination. Finally, 3%-doped sample exhibited the highest intrinsic quantum yield (81%), which qualifies these materials to be used as red-emitting components for solid-state lighting.(c) 2022 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 19/13371-3 - Luminóforos emissores vermelhos baseados em BaY2O4:Eu(III),Ce(III) para aplicação em WLEDs
• Beneficiário: Leonardo Figueiredo Saraiva
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica