Glass - Back to the Future!

Presenting Author:
Dušan Galusek1

article posted 21 March

Prof. Dušan Galusek has been working in the area of structural ceramic composites, and functional glasses since 1991. After earning his PhD at the Slovak University of Technology in Bratislava in 1995 he spent several years working at various research institutions abroad, including Brunel University in London, University of Leeds, Darmstadt University of Technology and Karlsruhe University of Technology. He became full professor in 2013, and in 2014 obtained the degree Doctor of Science (DSc.). He coordinated more than ten national and five international research projects, authored and co-authored 80 peer reviewed papers in scientific journals and more than one hundred contributions in conference proceedings, which have been cited more than 450 times. He is author and co-author of 4 books. At present he is head of the Centre of excellence for ceramics, glass, and silicate materials, and serves as the vice-rector for research, science, and international relations of the Alexander Dubcek University of Trencín. His present scientific interests include luminescent glasses, corrosion of glass and ceramics, and transparent ceramic materials.

Transition metals doped aluminate and aluminosilicate glasses with broadband luminescence in visible wavelengths

Róbert Klement1, Katarína Haladejová1, Peter Veteška2, Jozef Kraxner1, Enrico Bernardo3 and Dušan Galusek1, *
1Joint Glass Centre of the IIC SAS, TnU AD, and FChPT STU, Trencín, Slovakia 2FChFT STU, Bratislava, Slovakia 3Dipartimento di Ingegneria Industriale, University of Padova, Italy.

Aluminate glasses are transparent in IR, UV and VIS, and as such, they represent an ideal host matrix for optically active dopants. Due to their lower phonon energies in comparison to common silicate glasses, non-radiative transitions are suppressed and high efficiency of luminescence can be expected. They are also able to accommodate higher concentrations of rare-earth dopants in comparison to their single- or polycrystalline counterparts of identical composition, such as yttrium- or ytterbium aluminium garnets, or the respective rare earth aluminate perovskites. The glasses also exhibit good mechanical properties, especially hardness, and high chemical and thermal resistance. The main disadvantage of aluminate glasses is that they are usually relatively difficult to prepare, especially in bulk. The Al2O3 as the main component of these glasses is, unlike silica, not a typical glass former. Preparation of the aluminate glasses thus requires intense source of heat due to their high melting temperatures. Specific precautions, such as high cooling rates of the melt, and prevention of heterogeneous nucleation by the use of containerless melting techniques are also required during their preparation due to their high tendency to crystallization. In our previous works we reported on successful application of flame synthesis for preparation of aluminate glass microspheres of various compositions in the pseudo-binary and ternary systems Al2O3-Y2O3 [1], Al2O3-Y2O3-SiO2 [2], Al2O3-La2O3 [3], Al2O3-Yb2O3 [4], and Al2O3-CaO-SiO2 [5] (Fig. 1). In the present work we prepared selected compositions doped with transition optically active additives, mainly Mn(II). Fig. 2 summarizes the results of measurement of luminescence spectra of Mn-doped yttrium aluminate (a) and gehlenite (b) glass. In all cases controlled annealing in reduction H2/N2 atmosphere was required to carry out the Mn(IV) -> Mn(II) conversion and to induce measurable luminescence in the visible wavelength region. All Mn-doped compositions were excited in near UV region, and exhibited strong broadband luminescence in visible region. The emitted wavelengths were strongly influenced by the host glass matrix. The electron transitions responsible for luminescence were identified and discussed in detail.

1. A. Prnová, R. Karell, D. Galusek, Ceramics-Silikáty, 52 [2] 109-114 (2008)
2. A. Prnová, A. et al, Opt. Mater., 33 1872-1878 (2011)
3. Haliaková A., et al., Ceram. Int. 38 5543–5549 (2012)
4. A. Prnová, Ceram. Int., 40 6179-84 (2014)
5. E. Bernardo, et al, Opt. Mater., 36 1243–1249 (2014)