Combustion Synthesis of SrAl<sub>2</sub>O<sub>4</sub>: Eu<sup>2+</sup>, Dy<sup>3+</sup> Phosphorescent Pigments for Glow-in-the-Dark Safety Markings
Radu Lazău,
Robert Ianoș,
Cornelia Păcurariu,
Diana Aylin Căpraru,
Andrei Racu,
Vlad Cornea
Affiliations
Radu Lazău
Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University of Timișoara, P-ța Victoriei No. 2, 300006 Timișoara, Romania
Robert Ianoș
Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University of Timișoara, P-ța Victoriei No. 2, 300006 Timișoara, Romania
Cornelia Păcurariu
Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University of Timișoara, P-ța Victoriei No. 2, 300006 Timișoara, Romania
Diana Aylin Căpraru
Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University of Timișoara, P-ța Victoriei No. 2, 300006 Timișoara, Romania
Andrei Racu
National Institute of Research & Development for Electrochemistry and Condensed Matter, INCEMC, Str. Dr. A. Păunescu Podeanu No. 144, 300569 Timisoara, Romania
Vlad Cornea
Faculty of Industrial Chemistry and Environmental Engineering, Politehnica University of Timișoara, P-ța Victoriei No. 2, 300006 Timișoara, Romania
This study deals with SrAl2O4: Eu2+, Dy3+ phosphor pigments prepared by an optimized perchlorate-assisted combustion synthesis and tested for developing glow-in-the-dark safety markings. Recipes with different oxidizer/fuel ratios were designed to create an in-situ reducing-reaction atmosphere and promote Eu3+ → Eu2+ reduction, which is responsible for the specific long-lasting, green emission of the pigments. The obtained data proved the efficiency of glycine-rich mixtures (up to 200% glycine excess), which led to improved optical features, as compared to the reference stoichiometric sample. The best results in terms of emission intensity and decay time were obtained in the case of 100% glycine excess. The sample with optimum emission characteristics was successfully tested in making glow-in-the-dark coatings applied to two different substrates and using pigment concentrations between 10 and 33% weight.
