Lattice constants, total energies and densities of state of technetium(Tc) and rhenium(Re) with different crystalline structures were calculated with the GGA+PBE function, ultra-soft pseudo-potential and plane wave me...Lattice constants, total energies and densities of state of technetium(Tc) and rhenium(Re) with different crystalline structures were calculated with the GGA+PBE function, ultra-soft pseudo-potential and plane wave method in first-principles. The results were compared with those of projector augmented wave(PAW) method in first-principles and experimental data. The lattice stability results prove that HCP phase is the most stable phase, which agrees well with those of PAW method in first-principles and CALPHAD method. Further analyses of densities of state also give the same result of lattice stability for HCP-, FCC-, BCC-Tc and Re. Analyses of atomic populations show that the lattice stability of technetium and rhenium is probably related to the electrons in p and d state.展开更多
Rhenium diselenide(ReSe_(2))has gathered much attention due to its low symmetry of lattice structure,which makes it possess in-plane anisotropic optical,electrical as well as excitonic properties and further enables R...Rhenium diselenide(ReSe_(2))has gathered much attention due to its low symmetry of lattice structure,which makes it possess in-plane anisotropic optical,electrical as well as excitonic properties and further enables ReSe_(2)have an important application in optoelectronic devices.Here,we report the thickness-dependent exciton relaxation dynamics of mechanically exfoliated few-layer ReSe_(2)flakes by using time-resolved pump–probe transient transmission spectroscopies.The results reveal two thickness-dependent relaxation processes of the excitons.The fast one correlates with the exciton formation(i.e.,the conversion of hot carriers to excitons),while the slow one is attributed to the exciton recombination dominated by defect-assisted exciton trapping besides photon emission channel.The decrease of scattering probability caused by defects leads to the increase of fast lifetime with thickness,and the increase of slow lifetime with thickness is related to the trap-mediated exciton depopulation induced by surface defects.Polarization-dependent transient spectroscopy indicates the isotropic exciton dynamics in the two-dimensional(2D)plane.These results are insightful for better understanding of excitonic dynamics of ReSe_(2)materials and its application in future optoelectronic and electronic devices.展开更多
Methyltrioxorhenium (MTO) and its derivatives were utilized as catalysts for a broad variety of organic reactions after the discovery of an easy synthetic access way to this class of compounds. Among the numerous char...Methyltrioxorhenium (MTO) and its derivatives were utilized as catalysts for a broad variety of organic reactions after the discovery of an easy synthetic access way to this class of compounds. Among the numerous characterization techniques, 17O-NMR spectroscopy and vibrational spectroscopy were exemplary discussed. The immobilization of MTO and its derivatives is of significant current interest as is the synthesis of chiral derivatives.展开更多
A new 1,3,4-oxadiazole-contanining rhenium（I） complex, with the formula [Re（CO）a（Bphen）（PTOP）], （Bphen = bathophe- nardine, PTOP = 4-（5-p-tolyl-1,3, 4-oxadiazd-2-yl） pyridine）, is synthesized and character...A new 1,3,4-oxadiazole-contanining rhenium（I） complex, with the formula [Re（CO）a（Bphen）（PTOP）], （Bphen = bathophe- nardine, PTOP = 4-（5-p-tolyl-1,3, 4-oxadiazd-2-yl） pyridine）, is synthesized and characterized by elemental analysis, IR, 1H NMR, UV-vis and luminescence spectroscopy. The double-layer electroluminescence devices based on the Re（l） complex have been fabricated by spin-coating technique. The turn-on voltage, maximum efficiency, and brightness for green emission obtained from the devices are 9 V, 2.1 cd/A and 165 cd/m^2, respectively.展开更多
The adsorption and mechanism of Re(Ⅶ)on resin D318 were studied using chemical methods and IR spectrometry.At pH 5.2,the static and dynamic saturation adsorption capacities were 351.4 and 366.5 mg·g-1,respective...The adsorption and mechanism of Re(Ⅶ)on resin D318 were studied using chemical methods and IR spectrometry.At pH 5.2,the static and dynamic saturation adsorption capacities were 351.4 and 366.5 mg·g-1,respectively.The adsorption behavior obeyed the Freundlich empirical equation and the adsorption rate constant k298 was 6.37×10-4s-1.The desorption percentage was up to 99.7%when 2.0 mol·L-1KSCN was used for dynamic desorption.展开更多
基金Project(20070533118) supported by the Doctoral Discipline Foundation of the Ministry of Education of ChinaProject(50871124) supported by the National Natural Science Foundation of ChinaProject supported by the Postdoctoral Foundation of Central South University, China
文摘Lattice constants, total energies and densities of state of technetium(Tc) and rhenium(Re) with different crystalline structures were calculated with the GGA+PBE function, ultra-soft pseudo-potential and plane wave method in first-principles. The results were compared with those of projector augmented wave(PAW) method in first-principles and experimental data. The lattice stability results prove that HCP phase is the most stable phase, which agrees well with those of PAW method in first-principles and CALPHAD method. Further analyses of densities of state also give the same result of lattice stability for HCP-, FCC-, BCC-Tc and Re. Analyses of atomic populations show that the lattice stability of technetium and rhenium is probably related to the electrons in p and d state.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12074202,12174207,and 11974190)the Natural Science Foundation of Tianjin City(Grant Nos.20JCQNJC00020 and 22JCYBJC00390)。
文摘Rhenium diselenide(ReSe_(2))has gathered much attention due to its low symmetry of lattice structure,which makes it possess in-plane anisotropic optical,electrical as well as excitonic properties and further enables ReSe_(2)have an important application in optoelectronic devices.Here,we report the thickness-dependent exciton relaxation dynamics of mechanically exfoliated few-layer ReSe_(2)flakes by using time-resolved pump–probe transient transmission spectroscopies.The results reveal two thickness-dependent relaxation processes of the excitons.The fast one correlates with the exciton formation(i.e.,the conversion of hot carriers to excitons),while the slow one is attributed to the exciton recombination dominated by defect-assisted exciton trapping besides photon emission channel.The decrease of scattering probability caused by defects leads to the increase of fast lifetime with thickness,and the increase of slow lifetime with thickness is related to the trap-mediated exciton depopulation induced by surface defects.Polarization-dependent transient spectroscopy indicates the isotropic exciton dynamics in the two-dimensional(2D)plane.These results are insightful for better understanding of excitonic dynamics of ReSe_(2)materials and its application in future optoelectronic and electronic devices.
基金This work was financially supported by FEK is grateful to the Funds of Chemical Industrie for continuous support KRJ thanks BASF for financial support.
文摘Methyltrioxorhenium (MTO) and its derivatives were utilized as catalysts for a broad variety of organic reactions after the discovery of an easy synthetic access way to this class of compounds. Among the numerous characterization techniques, 17O-NMR spectroscopy and vibrational spectroscopy were exemplary discussed. The immobilization of MTO and its derivatives is of significant current interest as is the synthesis of chiral derivatives.
文摘A new 1,3,4-oxadiazole-contanining rhenium（I） complex, with the formula [Re（CO）a（Bphen）（PTOP）], （Bphen = bathophe- nardine, PTOP = 4-（5-p-tolyl-1,3, 4-oxadiazd-2-yl） pyridine）, is synthesized and characterized by elemental analysis, IR, 1H NMR, UV-vis and luminescence spectroscopy. The double-layer electroluminescence devices based on the Re（l） complex have been fabricated by spin-coating technique. The turn-on voltage, maximum efficiency, and brightness for green emission obtained from the devices are 9 V, 2.1 cd/A and 165 cd/m^2, respectively.
基金Supported by the National Natural Science Foundation of China （30972405） and the Natural Science Foundation of Zhejiang Province （Y3090531）.
文摘The adsorption and mechanism of Re(Ⅶ)on resin D318 were studied using chemical methods and IR spectrometry.At pH 5.2,the static and dynamic saturation adsorption capacities were 351.4 and 366.5 mg·g-1,respectively.The adsorption behavior obeyed the Freundlich empirical equation and the adsorption rate constant k298 was 6.37×10-4s-1.The desorption percentage was up to 99.7%when 2.0 mol·L-1KSCN was used for dynamic desorption.
