A series of polycrystalline Li 3 Ba 2 La 3Àx Eu x (MoO 4 ) 8 samples were prepared by the conventional solidstate reaction. The phase formation of the samples was investigated by X-ray diffraction measurements. The luminescence spectra and decay curves were studied as a function of Eu 3+ concentration and temperature. It turned out that the optical band gap of the undoped molybdates is at 3.65 eV. The quantum efficiency (QE) of the Eu 3+ doped luminescent materials increases with increasing Eu 3+ concentration and almost 100% QE was obtained for those samples doped with 70, 80, or 90% Eu 3+ . A sample containing 100% Eu 3+ showed solely a slight decrease in quantum efficiency. The luminous efficacy (LE) was 330 and 312 lm W opt À1 for the 10 and 100% Eu 3+ doped samples, respectively. The decrease of LE values is caused by a slight shift of the colour point to the red spectral range with increasing Eu 3+ content. Temperature dependent measurements revealed that Li 3 Ba 2 Eu 3 (MoO 4 ) 8 loses only 15% of efficiency up to 400 K, which demonstrates that the investigated phosphors are attractive for application in pcLEDs.

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The paper presents the method of preparation YAG:Ce precursor powder with ability for synthesis at lower temperature. Mechanochemical processing of an initial powder mixture was used as a preliminary step for subsequent high-temperature treatment of the precursor. The specific surface area, phase composition and luminescence properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. It has been shown that YAG structure formed at lower temperature by 300• C in comparison to the reference specimen but luminescence intesity was dependant on temperature of powder synthesis. The highest luminescence intensity was observed for powders synthesised at 1650• C. Keywords: mechanochemical processing, phosphor, YAG:Ce garnet W artykule przedstawiono otrzymywanie proszku granatu YAG:Ce z zastosowaniem zmodyfikowanej metody reakcji w stanie stałym. Mieszanina proszków wyjściowych została poddana procesowi aktywacji mechanochemicznej celem zwiększenia jego reaktywności podczas syntezy wysokotemperaturowej. Zbadano wpływ aktywacji na powierzchnię właściwą wyjściowej mieszaniny proszków. Proszek wygrzewany w różnych temperaturach został poddany analizie fazowej (XRD) oraz obserwacji na mikroskopie skaningowym (SEM). Zbadano niektóre właściwości optyczne: absorpcję i luminescencję przy wzbudzeniu λ=450 nm. Wykazano, że w wyniku aktywacji mechanochemicznej proszku wyjściowego YAG następuje obniżenie temperatury otrzymywania jednofazowego granatu itrowo-glinowego o 300• C, natomiast intensywność luminescencji zależała od temperatury syntezy; najwyższą uzyskano po syntezie w 1650• C.

The use of thick films becomes more and more important in particular for electronic and microelectronic applications. The term “thick film ” does not relate so much to the thickness of the film but more to the kind of deposition. Thick films are made by low-priced processes such as doctor (dr) blading, screen-printing, or spraying methods, etc. The preparation of thick films of ceramic material by these methods generally implies a processing sequence of the following steps: preparation of the oxide powders; preparation of pastes and slurries; painting/printing, etc.of the pastes onto a suitable substrate; drying at low temperature; and sintering at high temperature to get a consolidated layer. These technologies and the fabricated thick films of thermoresistive and superconducting materials will be discussed.