| Texto completo | |
| Autor(es): |
Fonseca, Karina T.
;
Santos, Nataly S.
;
Portes, Marcelo C.
;
Garcia, Fernando A.
;
Rodrigues, Lucas C. V.
Número total de Autores: 5
|
| Tipo de documento: | Artigo Científico |
| Fonte: | ACS OMEGA; v. 10, n. 30, p. 11-pg., 2025-07-22. |
| Resumo | |
Rare-earth oxysulfides (RE2O2S, RE3+ = Y, La, Gd, Lu) are promising matrices for luminescent materials due to their high thermal and chemical stability, cost-effectiveness, and efficient sensitization of trivalent lanthanide ions, leading to high luminescent efficiency. These compounds crystallize in a trigonal structure, belonging to the space group P3m1. Lutetium oxysulfide (Lu2O2S) has been extensively studied as a host material for three-dimensional plasma display panels, field emission displays, and light-emitting diodes. Lu2O2S:Eu3+ exhibits red persistent luminescence, while Lu2O2S:Ti features a broad orange emission band associated with titanium. The incorporation of Mg2+ enhances afterglow duration by creating charge compensation defects and facilitating energy storage in trap levels. This work investigates the crystalline structure, optical absorption, and persistent luminescence properties of Lu2O2S and its doped variants: Lu2O2S:Eu3+, Lu2O2S:Ti, and Lu2O2S:Mg2+. Additionally, codoping effects were explored in Lu2O2S:Eu3+,Ti, Lu2O2S:Eu3+,Mg2+, Lu2O2S:Ti,Mg2+, and Lu2O2S:Eu3+,Ti,Mg2+. The materials were synthesized for the first time via a rapid and energy-efficient microwave-assisted solid-state method. Phase purity and crystal structure were analyzed by X-ray diffraction (XRD) with Rietveld refinement. The incorporation of Eu3+, Ti and Mg2+ was assessed along with resulting structural modifications. Lu2O2S band gap energy was obtained with Kubelka-Munk function on the diffuse reflectance spectroscopy (DRS) data. X-ray Absorption Near Edge Structure (XANES) and X-ray Excited Optical Luminescence (XEOL) measurements confirmed that absorption by the matrix at the Lu L3-edge effectively induces luminescence, playing a positive role in the emission mechanism. EPR spectra of Lu2O2S:Ti and Lu2O2S:Eu3+,Ti materials suggested that, even though Ti3+ might be present, photoredox processes are absent in the persistent luminescence mechanism and that Ti remains in the Ti4+ state. The observed visible-light emissions upon UV and X-ray excitation, along with the high energy storage capacity, highlight the potential of these materials for applications in dosimetry, bioimaging, and optoelectronic devices. (AU) | |
| Processo FAPESP: | 24/12789-2 - Investigação estrutural de compostos de lantanídeos utilizando a técnica de Ressonância Paramagnética Eletrônica (EPR) em função do campo ligante |
| Beneficiário: | Marcelo Cecconi Portes |
| Modalidade de apoio: | Bolsas no Brasil - Programa Fixação de Jovens Doutores |
| 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: | 21/08111-2 - 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 |
| 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 |