Up-conversion luminescence in Yb(3+)-Er(3+)Tm(3+) co-doped Al(2)O(3)-TiO(2) nano-composites

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

doi:10.1016/j.jcis.2017.02.018

Up-conversion luminescence in Yb(3+)-Er(3+)Tm(3+) co-doped Al(2)O(3)-TiO(2) nano-composites

J Colloid Interface Sci. 2017 Jun 15:496:87-99. doi: 10.1016/j.jcis.2017.02.018. Epub 2017 Feb 13.

Authors

Teboho Patrick Mokoena¹, Ella Cebisa Linganiso¹, Vinod Kumar², Hendrik C Swart¹, So-Hye Cho³, Odireleng Martin Ntwaeaborwa⁴

Affiliations

¹ Department of Physics, University of the Free State, P.O. Box 339, Bloemfontein ZA 9300, South Africa.
² Photovoltaic Laboratory, Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016, India.
³ Materials Architecturing Research Centre, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 02792, Republic of Korea.
⁴ School of Physics, University of the Witwatersrand, Private Bag X3, Wits, 2050, South Africa. Electronic address: ntwaeab@gmail.com.

PMID: 28214627
DOI: 10.1016/j.jcis.2017.02.018

Abstract

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 ∼36nm. 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 980nm and the prominent emission bands were observed in the visible region at 523, 548 and 658nm 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 800nm for the Yb³⁺-Tm³⁺ co-doped systems. These upconverted emissions and energy transfer mechanisms taking place are discussed in detail.

Keywords: Alumina-titania nano-composites; Sol-gel; Up-conversion mechanism; Visible to NIR emissions.

Publication types

Research Support, Non-U.S. Gov't