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The main drawbacks of fluorescent activated lanthanide luminescent materials in practical optoelectronic applications are the high cost of raw material and the limitation of a specific color depending on the lanthanide ion. In this work, the synthesis of red, white and blue light emitting composite powders of Al 2 O 3 :Eu 3+ @SiO 2 were successfully synthesized by the hydrolysis and condensation reactions of TEOS as the raw precursor of silica matrix on the Al 2 O 3 :Eu 3+ surface. With the aim to change the CIE coordinates different weight ratios of Al 2 O 3 :Eu 3+ /SiO 2 powders from 13Al/87Si to 5Al/95Si were prepared. Besides, various excitation wavelength from 280 to 340 nm was used in order to change the ratio intensity; I red /I blue , between the red emission coming from the 5 D 0 → 7 F 2 transition of Eu 3+ ions and the blue band of silica matrix. Chemical evolution of the hydrolysis and condensation reaction of TEOS were conducted by FTIR spectroscopy. The results indicate that from 500˚C a complete TEOS to SiO 2 transformation is carried out.

In this work, the synthesis of undoped and Tm-doped ZnS nanoparticles is successfully carried out by the polyol method. From XRD analyses, it was confirmed that both types of particles possess the cubic zinc blend structure of the ZnS, and that the structure is not altered by doping. The crystallite size computed by the Scherrer equation is about 9 ± 1 nm. From photoluminescence analyses, the results show that the excitation spectrum has two excitation peaks at 304 nm and 356 nm; by exciting at 304 nm, a strong blue emission is observed at 420 nm, while exciting at 356 nm the characteristic Tm transition 1 G 4 → 3 H 6 is observed at 417 nm. By doping with Tm ions, the emission color changes from pure blue to sky according to the change in CIE coordinates from x = 0.15, y = 0.015 to x = 0.18, y = 0.17, respectively.

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