Effects of post calcination treatment on photoluminescence and structural properties of scheelite-type LiEuW2O8 nanocrystals synthesized by glycothermal reaction

Ryo Kasuya, Tetsuhiko Isobe, Shinobu Yamao, Hocine Sfihi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The scheelite-type LiEuW2O8 (LEW) nanoparticles of ∼50 nm in diameter were synthesized from lithium acetate, europium (III) acetate and phosphotungstic acid in 1,4-butylene glycol at 300°C for 2h by autoclave treatment. Post calcination treatment at 600°C for 2 h enhanced the photoluminescence at 465 nm due to the 4f - 4f transition excitation of Eu3+ by a factor of 24.4, and due to charge transfer (CT) excitation from either O2- or WO42- to Eu3+ by a factor of 5.8. Convergent beam electron diffractmetry and the compositional analysis revealed the non-stoichiometric structure of the scheelite-type LEW nanocrystals. Raman spectroscopy also detected the WO4 vibrational modes due to the tetragonal scheelite-type LEW. Solid-state 7Li single pulse excitation MAS NMR indicated the existence of at least three Li sites in the samples. We conclude that the following three factors are improved by calcination to increase the f-f transition probability of Eu3+: (i) a distribution of the Eu3+ - Eu3+ distance, (ii) the symmetry of Eu3+ polyhedra, (iii) the symmetry of tetrahedral WO 4 units in the vicinity of Eu3+ polyhedra. Furthermore, oxygen is provided for non-stoichiometric LEW during calcination to enhance the CT probability.

Original languageEnglish
Title of host publicationNanofunctional Materials, Nanostructures and Novel Devices for Biological and Chemical Detection
PublisherMaterials Research Society
Pages155-160
Number of pages6
ISBN (Print)9781604234077
DOIs
Publication statusPublished - 2006 Jan 1
Event2006 MRS Fall Meeting - Boston, MA, United States
Duration: 2006 Nov 272006 Dec 1

Publication series

NameMaterials Research Society Symposium Proceedings
Volume951
ISSN (Print)0272-9172

Other

Other2006 MRS Fall Meeting
CountryUnited States
CityBoston, MA
Period06/11/2706/12/1

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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    Kasuya, R., Isobe, T., Yamao, S., & Sfihi, H. (2006). Effects of post calcination treatment on photoluminescence and structural properties of scheelite-type LiEuW2O8 nanocrystals synthesized by glycothermal reaction. In Nanofunctional Materials, Nanostructures and Novel Devices for Biological and Chemical Detection (pp. 155-160). (Materials Research Society Symposium Proceedings; Vol. 951). Materials Research Society. https://doi.org/10.1557/proc-0951-e03-29