Enhancement of optical properties of Lu3Al5O12:Ce3+ and Ca-α-SiAlON:Eu2+ by quinine sulphate

Up to now, luminescence properties of Eu 2+ -activated Ca-α-Sialon (Ca-α-Sialon:Eu 2+ ) and Ce 3+ -doped lutetium aluminium garnet (LuAG:Ce 3+ ) have been widely studied in free or encapsulated forms in polymeric matrices individually. On the other hand, quinine sulphate (QS), which has been accepted as a “quantum yield standard” for the fluorescence spectroscopy due to the excellent emission performance, has also been investigated many times, for different purposes. In this work, we studied excitation and emission behaviour of quinine sulphate–phosphor blends consisting of Ca-α-Sialon:Eu 2+ /QS and LuAG:Ce 3+ /QS in polymethyl methacrylate matrix for the first time. The Ca-α-Sialon exhibited approximately 44% increase in the emission intensity when encapsulated along with the Quinine sulphate in the solid state. Similarly, the LuAG:Ce 3+ exhibited 98% increased brightness when used in QS containing PMMA matrix. Decay time measurements performed in nanosecond and microsecond time scales supported a potential energy transfer from the QS to the phosphors. The promising results obtained in this study may open a cost-effective way to enhance the optical performance of the both phosphors, which are basic materials for the fabrication of LED bulbs, smartphone and televisions screens, monitors, and panels of other electronic devices.