Li B.,Key Laboratory of Bioinorganic and Synthetic Chemistry |
Shi J.,Qingdao Agricultural University |
Zhang W.,Key Laboratory of Bioinorganic and Synthetic Chemistry |
Wang J.,Key Laboratory of Bioinorganic and Synthetic Chemistry |
And 2 more authors.
Journal of the Electrochemical Society | Year: 2010
A series of green long-lasting phosphorescence materials Ca8 Mg (SiO4) 4 Cl2: Eu2+, RE3+ (RE=La-Lu) was systematically investigated by long-lasting phosphorescence and thermoluminescence spectra. The green phosphorescence predominates at 502 nm due to the 4 f6 5d→4 f7 transition of the Eu 2+ ion. It strongly depends on the co-doped rare-earth ion, and its performance decreases in the order Nd>Sm>Ho>Dy>Ce>Pr>La> Gd>Tm>Er>Tb>Lu; for the Yb ion, the phosphorescence is totally quenched. The thermoluminescence properties show that there are generally four peaks around 330, 370, 435, and 470 K in the temperature range of 293-577 K, associated with the foreign defects due to the aliovalent substitution of rare-earth ions. The relationship of the long-lasting phosphorescence and thermoluminescence properties show that the difference in trap depth and the density of charge trapping centers and trapped charges, associated with thermoluminescence characteristics in the temperature range of 300-400 K, is responsible for the regular variation in the green long-lasting phosphorescence. The thermoluminescence spectrum of Ca8 Mg (SiO4) 4 Cl2: Eu2+, Nd3+ is fitted by the general kinetic model. The most appropriate trap depth in the present host is estimated to be around 0.8 eV, and the kinetic-order parameter b is 1.14. © 2010 The Electrochemical Society. Source
Wang B.-Y.,Key Laboratory of Bioinorganic and Synthetic Chemistry |
He C.-T.,Key Laboratory of Bioinorganic and Synthetic Chemistry |
Huang B.,Key Laboratory of Bioinorganic and Synthetic Chemistry |
Xu W.-J.,Key Laboratory of Bioinorganic and Synthetic Chemistry |
And 4 more authors.
Science China Chemistry | Year: 2015
A new bromethyl-substituted molecular rotor, [Cu(dabcoCH2Br)(H2O)Br3] (dabcoCH2Br+=1-(2-bromethyl)-1,4-diazoniabicyclo[2.2.2]octane cation), which belongs to a family of halomethyl-substituted molecular rotors, was synthesized and structurally characterized. The reversible phase transition at ca. 250 K was well established for this molecular rotor by thermal analyses, variable-temperature X-ray diffraction, and variable temperature dielectric measurements. The order-disorder transformation of the rotator part (dabco moiety) causes ferroelastic phase transition with an Aizu notation of mmmF2/m from high-temperature orthorhombic phase (Pbnm) to low-temperature monoclinic phase (P21/n). More important, in reference to the density functional theory calculations and structural analyses, the key factors to tune the phase transition behaviors are discussed in detail for this family of halomethyl-substituted molecular rotors. © 2015 Science China Press and Springer-Verlag Berlin Heidelberg Source