Abstract: While many of natural minerals, functional ceramic and glass materials are either oxides, chalcogenides or halides, the mixed-anion compounds, which contain several different anions, have now drawn attention as new types of inorganic material. Because of unique coordination, crystal structures and tunability of valence band in such mixed-anion compounds, it is possible that fundamentally different, innovative functions may be created. Materials with such innovative functions are expected to be created by using several different anions with differing electronegativity and polarizability, and exploiting the exceptional ability of such anions to control chemical bonding and electronic structures. In addition, many elements that become anions have a high Clarke number, and mixed-anion compounds have the possibility of becoming materials that act as a driving force for element strategies.

In this talk, some examples of development of new luminescent materials will be introduced by giving asymmetric ligand field to the active center and achieving lower excitation energy of charge transfer band by the valence band engineering in oxynitride and oxyhydride systems. Also examples of oxyfluoride glass ceramics will be presented, which have both formability of silicate glasses and high luminescent efficiency because of low phonon energy environment around the active ions.

Keywords: Luminescence, Rare-earth, Ligand field, Mixed-anion, Oxynitride, Oxyhidride

Biography: Professor Setsuhisa Tanabe received Dr. Eng. at Department of Industrial Chemistry, Kyoto University (KU) in 1993. After working as an assistant professor, he was promoted to an associate professor in 2001 and to a full Professor in 2008 all in KU. He is the author of 250 original papers, 27 book chapters, and 51 review papers on rare-earth doped luminescent materials for upconversion lasers, optical amplifier for telecommunication, LED phosphors, quantum-cutters and persistent phosphors. He has served as a plenary, keynote or invited speaker at 150 international conferences.
He was the Chair of TC20 (Optoelectronic Glasses) of International Commission on Glass (ICG) during 2003-2011 and is now a member of Steering Committee of ICG since 2013. He is Associate Editor of Journal of Luminescence and Fellow of SPIE. He got various awards from The American Ceramic Society (2018), The Ceramic Society of Japan (2009), The Chemical Society of Japan (1998), The Rare-Earth Society of Japan (2002), and ICG (2012). His publications receive 8638 citations (h-index: 47) according to Scopus.