Microwave-assisted hydrothermal synthesis of Eu2O3-coated spherical Y2O3 ceramic particles

Abstract This paper reports on the synthesis of uncoated and Eu 2 O 3 -coated spherical Y 2 O 3 ceramic particles using optimized hydrothermal (HM) and microwave-assisted hydrothermal (MWHM) routes. The integration of microwave and hydrothermal processes was shown to enhance the reaction kinetics during the synthesis of uncoated Y 2 O 3 . Spherical particles of pure Y 2 O 3 phase with an average particle size of 600 nm and uniform size distribution were obtained via the MWHM process at 180 °C following reaction duration of only 1 h. Y 2 O 3 spherical particles were coated with Eu 2 O 3 via a hydrolysis method at room temperature. The band gap of the resulting phosphors was estimated at 5.7 eV. Eu 2 O 3 -coated Y 2 O 3 particles synthesized via the HM and MWHM present bright red PL emission under UV excitations; however, Y 2 O 3 particles obtained via the MWHM method are more efficient than those yielded via the HM technique. Eu 2 O 3 -coated Y 2 O 3 particles derived using the optimized MWHM technique present efficient emissions of red light with color purity and down conversion efficiency of approximately 85% and 80%, respectively. The present study demonstrates the suitability of employing coated phosphors in optical display technologies.