UPCONVERSION IN YTTRIUM VANADATE MATRIX OBTAINED BY NON-HYDROLYTIC SOL-GEL METHODOLOGY

Purpose: In this work the yttrium vanadate matrix was synthesized contend the lanthanides Er 3+ and Er 3+ /Yb 3+ , by non-hydrolytic sol-gel methodology. Methods: The synthesis were performed using metal chloride as precursors. The molar ratio of lanthanides ions was 1% in relation of the yttrium ion. The sample was treated at 800 oC during 4 h, the final products were characterized by X-rays (XRD) diffraction and up conversion photoluminescence (PL). Results: The analyses XRD before the heat treatment showed the mixture of chlorides used as precursor material in the non-hydrolytic sol-gel process, after the heat treatment the XRD presented peaks ascribed to the YVO 4 phase tetragonal (card 72-274). The emission spectrum were use to laser system with excitation wavelength fixed at 980 nm and varying the power in 0.5 until 2.0 W. The emission spectrum of the samples containing only Er 3+ ion and the pair Er 3+ /Yb 3+ presented intense bands in the green region (545nm) of the electromagnetic spectrum, corresponding to the transition 4 S 3/2 ® 4 I 15/2 , with intensities dependent on laser power. The addiction of the Yb 3+ ion in the matrix influenced of the emission intensity, the matrix containing the ion pair being twice of that one with only Er 3+ ion, this fact is in agreement with the expected energy transfer from the infrared to visible region. Conclusion: The intense emission in the green region opens up good prospects for applications such as nanothermometer and solar cells.