Abnormal co-doping effect on the red persistent luminescence SrS:Eu2+,RE3+ materials

Autor(es)

Almeida dos Santos, Danilo Ormeni ^[1] ; Giordano, Luidgi ^[1] ; Stock Grein Barbara, Miguel Aguirre ^[1] ; Portes, Marcelo Cecconi ^[1] ; Santos Pedroso, Cassio Cardoso ^{[2, 3]} ; Teixeira, Veronica Carvalho ^[4] ; Lastusaari, Mika ^[5] ; Veloso Rodrigues, Lucas Carvalho ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Fundamental Chem, Inst Chem, BR-05508000 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Chem, Dept Biochem, BR-05508000 Sao Paulo, SP - Brazil

^[3] Lawrence Berkeley Natl Lab, Mol Foundry, Berkeley, CA 94720 - USA

^[4] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Synchrotron Light Lab LNLS, BR-13083970 Campinas, SP - Brazil

^[5] Univ Turku, Dept Chem, FI-20014 Turku - Finland

• Tipo de documento: Artigo Científico
• Fonte: DALTON TRANSACTIONS; v. 49, n. 45, p. 16386-16393, DEC 7 2020.
• Citações Web of Science: 1

Resumo

Persistent luminescence materials are a reality in several applications. However, there is still a lack of efficient red-emitting materials. SrS:Eu2+ phosphor is a potential candidate since its strong nephelauxetic effect shifts Eu(2+)4f(6)5d(1) -> 4f(7) to red, and its weak bond between strontium and sulphide, due to the soft base-hard acid character, generates a high number of intrinsic defects. SrS:Eu2+,RE3+ materials were efficiently prepared by two rounds of 22 min microwave-assisted solid-state synthesis. The highly crystalline purity and the material organization at the micro-scale were observed with X-ray powder diffraction and scanning electron microscopy, respectively. X-ray absorption spectroscopy revealed a low amount of Eu2+ compared to Eu3+ due to the efficient Eu2+ photo-oxidation by X-ray irradiation in the high storage capability SrS host matrix. Electron paramagnetic resonance spectra confirmed that at least 50% of Eu2+ ions in the material are photo-oxidized during excitation, reinforcing the previously established mechanisms. The RE2+ energy level positioned very close to or into the conduction band led to an abnormal co-doping effect, with similar effects independent of the co-dopant. The high concentration of intrinsic defects in SrS indicates that the soft-hard pair host is an excellent approach to develop efficient persistent luminescence materials. (AU)

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