Probing structural defects and X-ray induced persistent luminescence mechanisms on rare earth-doped strontium sulfide materials

Autor(es)

Fonseca, Karina T. ; Santos, Danilo O. A. ; Garcia, Fernando A. ; Rodrigues, Lucas C. V.

• Tipo de documento: Artigo Científico
• Fonte: DALTON TRANSACTIONS; v. 54, n. 15, p. 14-pg., 2025-03-06.

Resumo

Persistent luminescence is related to the existence of point defects in the crystal structure, which can be induced by the insertion of dopant ions to create trap levels for charge carriers. Strontium sulfide (SrS) is a promising host for X-ray activated phosphors due to its high luminescence yield and X-ray absorption efficiency. While the mechanisms of UV- and visible light-induced luminescence in rare-earth doped SrS have been previously explored, this work focuses on understanding X-ray induced mechanisms using synchrotron radiation techniques. Extended X-ray absorption fine structure (EXAFS) analysis suggested that rare-earth ions incorporate into the SrS lattice primarily as substitutional defects, with structural distortions depending on the differences in ionic radii between Sr2+ and RE2+/3+. X-ray absorption near edge structure (XANES) spectra revealed the mixed-valence nature of Ce in SrS:Ce and SrS:Eu,Ce materials, and also that X-ray irradiation triggers complex charge transfer processes. The X-ray excited optical luminescence (XEOL) results showed that co-doped samples exhibited longer persistent luminescence decay times than their single-doped counterparts due to the increased number of defects. These findings provide new insights into the interplay between crystal defects and persistent luminescence in X-ray-activated phosphors, contributing to the design of more efficient materials for applications such as medical imaging, optical information storage, and industrial sensing. (AU)

• Processo FAPESP: 22/11983-4 - Espectroscopias com intensificação de sinal: nanomateriais, teoria e simulação computacional
• Beneficiário: Mauro Carlos Costa Ribeiro
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 21/05603-1 - Estudos avançados de espectroscopias ópticas e de raios X para dominar os processos de transferência de carga em materiais luminescentes
• Beneficiário: Lucas Carvalho Veloso Rodrigues
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 19/25665-1 - Instabilidades de carga e spin em supercondutores não convencionais
• Beneficiário: Fernando Assis Garcia
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 19/26689-1 - Luminescência persistente induzida por raios X e aplicações
• Beneficiário: Karina Torre da Fonseca
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 21/08111-2 - Materiais conversores de luz à base de terras raras: marcadores luminescentes, sensores e amplificadores ópticos
• Beneficiário: Hermi Felinto de Brito
• Modalidade de apoio: Auxílio à Pesquisa - Temático