Synthesis and characterization of Sr ₃ Al ₂ O ₆ :Eu ²⁺ , Dy ³⁺ phosphors prepared by sol–gel–combustion processing

Abstract

A type of red luminescent Sr3Al2O6:Eu2+, Dy3+ phosphor powder is synthesised by sol–gel–combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions. By tracing the formation process of the sol–gel, it is found that it is necessary to reduce the amount of NO−3 by dropping ethanol into the solution for forming a stable and homogeneous sol–gel. Thermogravimetric and Differential Scanning Calorimeter Analysis, x-ray diffractionmeter, scanning electron microscopy and photoluminescence spectroscopy are used to investigate the luminescent properties of the as-synthesised Sr3Al2O6:Eu2+, Dy3+. The results reveal that the Sr3Al2O6 crystallises completely when the combustion ash is sintered at 1250 °C. The excitation and the emission spectra indicate that the excitation broadband lies mainly in a visible range and the phosphors emit a strong light at 618 nm under the excitation of 472 nm. The afterglow of (Sr0.94Eu0.03Dy0.03)3Al2O6 phosphors sintered at 1250 °C lasts for over 1000 s when the excited source is cut off.