Up-conversion luminescence in Yb3+-Er3+/Tm3+ co-doped Al2O3-TiO2 nano-composites

Teboho Patrick Mokoena, Ella Cebisa Linganiso, Vinod Kumar, Hendrik C. Swart, So Hye Cho, Odireleng Martin Ntwaeaborwa

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


The sol gel method was used to prepare rare-earths (Yb3+-Er3+ and Yb3+-Tm3+) co-doped Al2O3-TiO2 nano-composite powder phosphors and their up-conversion luminescence properties were investigated. Mixed oxides of titania (TiO2) rutile phase and an early stage crystallization of alumina (Al2O3) phase were confirmed from the X-ray diffraction data with the average crystallite size of ∼36 nm. The rutile phase TiO2 was further confirmed by selected area diffraction analysis of the composites. Microscopy analysis showed interesting rod-like morphologies with rough surfaces indicating that a spherulitic growth process took place during the crystal growth. Photoluminescence characterization of the phosphors was carried out under near infra-red excitation at 980 nm and the prominent emission bands were observed in the visible region at 523, 548 and 658 nm for the Yb3+-Er3+ co-doped systems. Emission in bands extending from the visible to near infra-red regions were observed at 480, 650, 693 and 800 nm for the Yb3+-Tm3+ co-doped systems. These upconverted emissions and energy transfer mechanisms taking place are discussed in detail.

Original languageEnglish
Pages (from-to)87-99
Number of pages13
JournalJournal of Colloid and Interface Science
Publication statusPublished - 15 Jun 2017
Externally publishedYes


  • Alumina-titania nano-composites
  • Sol-gel
  • Up-conversion mechanism
  • Visible to NIR emissions

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Surfaces, Coatings and Films
  • Colloid and Surface Chemistry


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