No abstract

a b s t r a c tWe present a rapid and energy-efficient microwave-assisted approach to prepare a single-phase fullcolor phosphor based on Ba 3 MgSi 2 O 8 . The samples were prepared using a citric acid based solegel preparation pathway with a microwave-assisted heating step, which reduces the time required for the final heat treatment to less than 30 min. Thermogravimetric analysis was utilized to optimize the solution-based preparation prior to microwave heating. The structural properties of the obtained luminescent materials have been thoroughly investigated by means of X-ray powder diffraction and Rietveld analyses. To study the optical behavior, the excitation and emission spectra were recorded. Fullcolor emission is achieved using Eu 2þ (blue), Tb 3þ (green), and Mn 2þ (red) as the activator ions. The thermally robust emission was investigated using temperature-dependent luminescence spectroscopy. The energy-transfer processes within the samples were studied using time-dependent spectroscopy, and the quantum yield of this true color phosphor as a function of the composition was determined.

The green-emitting title phosphors a prepared by an optimized fast and energy-efficient citrate based sol-gel reaction with subsequent combustion in a domestic microwave oven leading to high quality materials in less than 25 min of final heating time. The samples, especially Ba 2 SiO 4 :Eu 2+ , show good quantum yields and are suitable for applications in green phosphor-converted light emitting diodes, or as green components in phosphor blends. -(BIRKEL*, A.; DECINO, N. A.; GEORGE, N. C.; HAZELTON, K. A.; HONG, B.-C.; SESHADRI, R.; Solid State Sci. 19 (2013) 51-57, http://dx.

Samples of Ba2.97-xEu0.03TbxMg1-xLixSi2O8 are prepared by microwave-assisted sol-gel reactions of BaCO 3, Mg(NO3)2, (Et-O)4Si, Tb(NO3)3, Eu(NO3)3, MnCO3, and Li2CO3 dissolved in a mixture of EtOH, H2O, AcOH, and citric acid (heating the obtained powder to 400 C for 4 h and to 650 C for 6 h). Microwave heating leads to materials with very high phase purity not obtainable using furnace--based preparation methods. Ba 2.64Eu0.06Tb0.3Mg0.68Mn0.02Li0.3Si2O8 exhibits red, green, and blue emission due to the dopant ions Eu 2+ , Tb 3+ , and Mn 2+ . The light produced is a cool white light with warmer colors limited by the solubility limit of Tb 3+ in Ba 3MgSi2O8. -(BIRKEL, A.; DECINO, N. A.; COZZAN, C.; MIKHAILOVSKY, A. A.; HONG, B.-C.; SESHADRI*, R.; Solid State Sci. 48 (2015) 82-89, http://dx.