Beschreibung:
<jats:p>Set of novel Eu<jats:sup>2+</jats:sup>-doped K<jats:sub>x</jats:sub>Na<jats:sub>1-x</jats:sub>LuS<jats:sub>2</jats:sub> phosphors (where x = 0 – 1) was successfully synthesized in the form of transparent crystalline hexagonal platelets by chemical reaction under the flow of hydrogen sulfide. Their physical properties were investigated by means of X-ray diffraction, X-ray excited fluorescence, time-resolved luminescence spectroscopy and electron paramagnetic resonance. Special attention is given to photoluminescence emission spectra under the 395 nm and 455 nm excitation aiming to obtain white emission with tunable color temperature, which is desirable for circadian white LEDs construction. EPR method is employed to understand the Eu<jats:sup>2+</jats:sup> incorporation and distribution in the K<jats:sub>x</jats:sub>Na<jats:sub>1-x</jats:sub>LuS<jats:sub>2 </jats:sub>hosts. CIE xy-coordinates are used to compare effects of different K/Na concentration in K<jats:sub>x</jats:sub>Na<jats:sub>1-x</jats:sub>LuS<jats:sub>2</jats:sub> on resulting spectrum (Figure 1). The application potential of mentioned compounds in the field of white LED solid state lighting phosphors with tunable color temperature is thoroughly discussed. The realistic circadian light bulb is presented as well and its properties are addressed.</jats:p>
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<jats:p>Figure 1</jats:p>
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