Tři nejdůležitější odborné publikace vydané během prvního období (do 31. března 2019). Seznam všech publikací výzkumného programu CHEMISTRY vydaných v rámci projektu CAAS najdete v předchozím příspěvku.
Highly luminescent cerium-doped YSO/ LSO microcrystals prepared via room temperature sol-gel route
K. Popovicha, M. Šípková, V. Čuba, L. Procházková, J. Bárta, M. Nikl
Available online 25 January 2019.
Luminescent properties of cerium-doped yttrium oxyorthosilicate (Y2SiO5; YSO) and lutetium oxyorthosilicate (Lu2SiO5; LSO) prepared by a room-temperature sol-gel route were studied and compared to those of YSO and LSO single crystals. Structural changes in the samples during calcination were also studied by X-ray diffraction and differential thermal analysis. Radioluminescence spectra of the samples show comparable emission intensity with the bulk materials. Photoluminescence decay measurements were used to investigate the decay characteristics of the prepared powders. Changes in luminescent properties after the reduction of particle size by grinding in a ball mill were also demonstrated on the YSO:Ce3+ sample. Acceleration of the faster component of the decay time from 7.1 ns to 6.2 ns was observed. Prepared YSO:Ce3+ and LSO:Ce3+ powders are suggested to be good candidates for fast imaging or other applications.
Extraction of thallium and indium isotopes as the homologues of nihonium into the ionic liquids
Katerina Cubova, Miroslava Semelova, Mojmir Nemec, Jan John, Juraj Milacic, Jon Petter Omtvedt, Jan Stursa
Extraction of thallium and indium, as the homologues of nihonium, from HCl solutions into hydrophobic ionic liquids was studied. In the presence of NaClO2 as the oxidizing agent, thallium is effectively extracted into all the tested ionic liquids from 0.2 to 5 M HCl. In absence of NaClO2, thallium extraction strongly depends on the HCl concentration and no extraction of indium was observed. Using [C6mim][NTf2] and [Tbma][NTf2], the thallium/indium separation factors SF(Tl/In) > 4 × 104 can be achieved. Hence, the system with NaClO2oxidizing agent can be considered a candidate for the future studies of nihonium chemical properties.
On the Structure, Synthesis and Characterization of Ultrafast Blue-Emitting CsPbBr3 Nanoplatelets
Kateřina Tomanová, Václav Čuba, Mikhail G. Brik, Eva Mihóková, Rosana Martinez Turtos, Paul Lecoq, Etiennette Auffray, and Martin Nikl
Recent developments in medical imaging techniques, in particular, those in time-of-flight positron emission tomography put new challenges on scintillating material performance that cannot be fulfilled by conventional scintillators. Bright and ultrafast nanoparticles represent promising candidates to build up an advanced detection system needed. We synthesize colloidal CsPbBr3 nanoplatelets emitting blue light with fast sub-nanosecond decay. We also prepare a nanocomposite material by embedding the nanoplatelets in the polystyrene matrix. We show that blue emission is preserved provided the composite is not exposed to UV/vis light and/or elevated temperatures. Motivated by conflicting information from the literature about the room temperature structure of colloidal CsPbX3 (X = Cl, Br, I) particles, that results being orthorhombic, rather than cubic, we perform ab initio electronic structure calculations of bulk crystals with an orthorhombic structure. We calculate optical properties, as well as exciton diameters and binding energies and compare them to those previously obtained for cubic CsPbX3 crystals.