Eu2+-doped M2SiO4 (M = Ca, Ba) phosphors prepared by a rapid microwave-assisted sol–gel method: Phase formation and optical properties

We present a rapid microwave-assisted approach for the preparation of Eu2+-doped orthosilicate phosphors. The preparation method relies on a citrate based sol–gel reaction with subsequent combustion in a domestic microwave oven, in contrast to more conventional solid-state methods. This sol–gel pathway yields phase pure, high quality orthosilicates, in less than 25 min of final heating time. In addition, superior morphology control is achieved employing the sol–gel method compared to solid-state preparations. In order to understand the formation process of the final products, thermogravimetric analyses and temperature-dependent X-ray diffraction data were acquired and compared to the conventional solid-state preparation. The morphology and elemental composition of the obtained luminescent materials were investigated using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The optical properties were elucidated by measuring room-temperature emission and excitation spectra, and the application and efficiency of the obtained phosphors in LED devices was studied.

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