CaWO₄:Yb³⁺,Tm³⁺ Crystals and SrAl₂O₄:Eu²⁺,Dy³⁺ Phosphors in Glass-Based Composites for Green Afterglow after NIR Excitation

¹ Photonics Laboratory, Tampere University, Korkeakoulunkatu 3, Tampere 33720, Finland
² Institute of Low Temperature and Structure Research PAS, Okolna 2, 50-422, Wrocław, Poland
³ Department of Chemistry, University of Turku, FI-20014 Turku, Finland
⁴ University of Turku Graduate School (UTUGS), Doctoral Programme in Exact Sciences, Turku, Finland
⁵ LumiLab, Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, 9000, Gent, Belgium.
⁶ Department of Physics, LUT-University, Yliopistonkatu 34, Lappeenranta 53850, Finland

^* Corresponding author: evellyn.santosmagalhaes@tuni.fi

Published online: 18 October 2023

Abstract

Here, we present the preparation of composites with green persistent luminescence using melting process. The composites are phosphate glass (75NaPO₃-25CaF₂ and 90NaPO₃-10NaF (in mol%)) with embedded phosphors: CaWO₄: Yb³⁺, Tm³⁺ crystals with blue upconversion and SrAl₂O₄:Eu²⁺,Dy³⁺ with green persistent luminescence. Green persistent luminescence above 0.3 mcd/m² can be seen for ~ 30 minutes after charging with 980 nm due to energy transfer between the blue upconverter crystals and the persistent luminescent phosphors. Challenges related to the fabrication of such composites are discussed.