| Autor: |
dos Santos, Danilo Ormeni Almeida, Giordano, Luidgi, Barbará, Miguel Aguirre Stock Grein, Portes, Marcelo Cecconi, Pedroso, Cássio Cardoso Santos, Teixeira, Verônica Carvalho, Lastusaari, Mika, Rodrigues, Lucas Carvalho Veloso |
| Předmět: |
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| Zdroj: |
Dalton Transactions: An International Journal of Inorganic Chemistry; 12/7/2020, Vol. 49 Issue 45, p16386-16393, 8p |
| Abstrakt: |
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 Eu2+4f65d1 → 4f7 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. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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