Novel synthesis of Eu-doped SiAlON luminescent materials from a preceramic polymer and nano-sized fillers

• Eu-doped β′-SiAlON feasible from polysilazane and nano-sized active fillers.
• Distribution of Eu in β′-SiAlON affected by the firing atmosphere (N2 or N2/H2).
• β′-SiAlON displaying blue and green emission, due to complex phase assemblage.
• α′-SiAlON developed for the first time from preceramic polymers and fillers.
• Polymer-derived Eu:Ca-α′-SiAlON showing distinctive yellow luminescence.

A commercial polysilazane, mixed with nano-sized fillers particles, has been used for the first time for the preparation of Eu-doped β′- and α′-SiAlON-based powders, exhibiting yellow, green and blue luminescence under blue or near UV excitation, depending on processing conditions. β′-Phase was obtained by mixing the preceramic polymer with both γ-Al2O3 and Si3N4 nanoparticles, whereas the Ca α-phase was achieved by adding γ-Al2O3 and CaCO3 nanoparticles. Rare-earth ions were provided by Eu2O3 nano-particles.The reduction of Eu3+ into Eu2+ incorporated in SiAlON was favored by the presence of carbon derived from the pyrolysis of the preceramic polymers. The nanometric distribution of filler materials and the high yield of the selected preceramic polymers in terms of Si and N atoms led to the formation of the desired phases at relatively low firing temperatures (e.g. 3 h at 1550–1600 °C in pure nitrogen).