Jan Długosz University

About: Jan Długosz University is a education organization based out in Częstochowa, Poland. It is known for research contribution in the topics: Crystal structure & Luminescence. The organization has 749 authors who have published 2311 publications receiving 19395 citations. The organization is also known as: Higher Teacher Education School.

Impacts of 5d electron binding energy and electron-phonon coupling on luminescence of Ce 3+ in Li 6 Y(BO 3 ) 3

Abstract: In this work, the crystal structure and electronic structure as well as the synchrotron radiation vacuum ultraviolet-ultraviolet-visible (VUV-UV-vis) luminescence properties of Li6Y(BO3)3 (LYBO):Ce3+ phosphors were investigated in detail. The Rietveld refinement and DFT calculation reveal the P21/c monoclinic crystal phase and the direct band gap of the LYBO compound, respectively. Only one kind of Ce3+ 4f–5d transition is resolved in terms of the low temperature VUV-UV excitation, UV-vis emission spectra and luminescence decay curves. Furthermore, by constructing the vacuum referred binding energy (VRBE) scheme and applying the frequency-degenerate vibrational model, the impacts of 5d electron binding energy and electron–phonon coupling on luminescence of Ce3+ in LYBO are analysed. The results show that the Ce3+ emission in LYBO possesses a moderate intrinsic thermal stability. With the increase in concentration, the thermal stability of the emission gets worse due to the possible thermally-activated concentration quenching. In addition, the simulation of Ce3+ emission profile at low temperature reveals that the 4f–5d electronic transitions of Ce3+ ions can be treated to couple with one frequency-degenerate vibrational mode having the effective phonon energy of ∼257 cm−1 with the corresponding Huang–Rhys parameter of ∼6, which indicates a strong electron–phonon interaction of Ce3+ luminescence in the Li6Y(BO3)3 host. Finally, the X-ray excited luminescence spectrum of the LYBO:5%Ce3+ phosphor is measured to check the potential scintillator applications.

Solvent-Free Michaelis–Arbuzov Rearrangement under Flow Conditions

Abstract: The first solvent- and catalyst-free procedure for the Michaelis-Arbuzov reaction under flow conditions was developed. A variety of alkylphosphonic esters could be obtained using this protocol starting from the corresponding trialkyl phosphites and even catalytic amounts of alkyl halides with very short reaction times (8.33-50 min) and excellent conversions. In general, this protocol works effectively when the alkyl halide is used in catalytic amounts as low as 5-10% only if it concerns the synthesis of homo alkylphosphonates. One equivalent and an excess of alkyl halides should be used in the reaction with alkyl phosphite if the alkyl group of the selected substrates differ. Thus, it provides a sustainable, fast alternative to the existing methods for the preparation of alkylphosphonates. The isolation of the reaction products is straightforward due to the lack of solvents and a high purity of the obtained products (conv ≥ 99%), and notably, in the catalytic procedures there are only traces of alkyl halides formed after the reaction is complete. The reactions conducted using a glass microreactor chip with an internal volume of 250 μL allow the production of 1.6-1.95 g of organophosphorus esters per hour.