Ionic liquid 1-methyl-3-(3-sulfopropyl) -imidazolium hydrogen sulfate([C3SO3HMIM][HSO4]) was synthesized and characterized by infrared spectroscopy(IR) ,nuclear magnetic resonance(1H and 13C NMR) and ultraviolet-visib...Ionic liquid 1-methyl-3-(3-sulfopropyl) -imidazolium hydrogen sulfate([C3SO3HMIM][HSO4]) was synthesized and characterized by infrared spectroscopy(IR) ,nuclear magnetic resonance(1H and 13C NMR) and ultraviolet-visible(UV-Vis) spectra. Its thermal stability was also examined by thermogravimetric analysis(TGA) and a differential scanning calorimeter(DSC) . The mole fraction solubilities of [C3SO3HMIM][HSO4]) in 12 selected solvents(n-pentane,n-hexane,n-heptane,benzene,toluene,ethylbenzene,acetone,2-butanone,3-methyl-2-butanone,tetrahydrofuran,ethyl acetate and dichloromethane) in the temperature range from 289.15 to 363.15 K were meas-ured using a static analytical method and correlated with an empirical equation.展开更多
Alkali metal(Li, Na, K) doped ZnO powders were synthesized by solid-state reaction at different calcination temperatures and holding time. Effects of holding time and K sources on the infrared emissivity of ZnO were i...Alkali metal(Li, Na, K) doped ZnO powders were synthesized by solid-state reaction at different calcination temperatures and holding time. Effects of holding time and K sources on the infrared emissivity of ZnO were investigated. The structure and surface morphologies of samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The UV-Vis absorption and infrared emissivities were investigated by a UV-Vis spectrophotometer and an infrared emissometer, respectively. XRD patterns confirm the wurtzite structure of the as prepared samples with single phase. Smooth grain surfaces are detected in all doped ZnO samples, while ZnO:Li and ZnO:Na present the aggregation of grains. The redshifts in the optical band-gap are observed in K-, Na-, and Li-doped ZnO with the values 3.150, 3.144, and 3.142 eV. Due to better crystalline quality, ZnO:K shows a lower emissivity than others. The emissivity of K-doped ZnO decreases to the minimum value(0.804), at 1200 °C and holding 2 h. Compared with KNO3 as K source, K2CO3 doped ZnO has lower emissivities.展开更多
Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the...Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure （fl-Ga203）. Structure analysis reveals a clear out-of-plane orientation offl-Ga203 （201） II A1203 （0001）. The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared （UV-vis-NIR） spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.展开更多
The nucleation and growth mechanism and polymorph-property correlations in the molecular cocrystal field are widely sought but currently remain unclear. Herein, a new wire-like morphology of phenazine(Phz)-chloranilic...The nucleation and growth mechanism and polymorph-property correlations in the molecular cocrystal field are widely sought but currently remain unclear. Herein, a new wire-like morphology of phenazine(Phz)-chloranilic acid(H2ca) cocrystal(PHC) is demonstrated for the first time, and the self-assembly of Phz and H2ca is controlled to selectively prepare kinetically stable wires and thermodynamically stable plates. Specifically, low precursor concentration is beneficial for one-dimensional(1D) self-assembly along the [010] crystallographic direction, while only supersaturation can trigger 2D self-assembly along the [100] and [010] directions, respectively. This is understandable in terms of the(020) face showing the largest attachment energy(Eatt) and the(002) face possessing the smallest surface energy(Esurf). Moreover, anisotropic Raman spectra related to the mode symmetry and atomic displacements in two types of PHCs are revealed, and the same Raman-active vibrational bands of PHC wire and plate show different polarization responses, which is intrinsically ascribed to their different molecular orientations.Overall, this is the first case that morphologies of cocrystal are precisely tuned with comprehensive investigations of their anisotropic vibrational characteristics.展开更多
文摘Ionic liquid 1-methyl-3-(3-sulfopropyl) -imidazolium hydrogen sulfate([C3SO3HMIM][HSO4]) was synthesized and characterized by infrared spectroscopy(IR) ,nuclear magnetic resonance(1H and 13C NMR) and ultraviolet-visible(UV-Vis) spectra. Its thermal stability was also examined by thermogravimetric analysis(TGA) and a differential scanning calorimeter(DSC) . The mole fraction solubilities of [C3SO3HMIM][HSO4]) in 12 selected solvents(n-pentane,n-hexane,n-heptane,benzene,toluene,ethylbenzene,acetone,2-butanone,3-methyl-2-butanone,tetrahydrofuran,ethyl acetate and dichloromethane) in the temperature range from 289.15 to 363.15 K were meas-ured using a static analytical method and correlated with an empirical equation.
基金Project(JB141405)supported by the Fundamental Research Funds for the Central Universities of China
文摘Alkali metal(Li, Na, K) doped ZnO powders were synthesized by solid-state reaction at different calcination temperatures and holding time. Effects of holding time and K sources on the infrared emissivity of ZnO were investigated. The structure and surface morphologies of samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The UV-Vis absorption and infrared emissivities were investigated by a UV-Vis spectrophotometer and an infrared emissometer, respectively. XRD patterns confirm the wurtzite structure of the as prepared samples with single phase. Smooth grain surfaces are detected in all doped ZnO samples, while ZnO:Li and ZnO:Na present the aggregation of grains. The redshifts in the optical band-gap are observed in K-, Na-, and Li-doped ZnO with the values 3.150, 3.144, and 3.142 eV. Due to better crystalline quality, ZnO:K shows a lower emissivity than others. The emissivity of K-doped ZnO decreases to the minimum value(0.804), at 1200 °C and holding 2 h. Compared with KNO3 as K source, K2CO3 doped ZnO has lower emissivities.
基金supported by the National Natural Science Foundation of China(Nos.61274113,61404091,61505144,51502203 and 51502204)the Opening Fund of Key Laboratory of Silicon Device Technology in Chinese Academy of Sciencesthe Tianjin Natural Science Foundation(Nos.14JCZDJC31500 and 14JCQNJC00800)
文摘Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure （fl-Ga203）. Structure analysis reveals a clear out-of-plane orientation offl-Ga203 （201） II A1203 （0001）. The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared （UV-vis-NIR） spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.
基金supported by the National Natural Science Foundation of China (51303185, 21021091, 51033006, 51222306, 51003107, 61201105, 3591027043, 91222203, 91233205, 21473222 and 21773040)the Ministry of Science and Technology of China (2011CB808400, 2011CB932300, 2013CB933403, 2013CB933500 and 2014CB643600)the Chinese Academy of Sciences (Y42D0A12D1 and Y42D0412D1)。
文摘The nucleation and growth mechanism and polymorph-property correlations in the molecular cocrystal field are widely sought but currently remain unclear. Herein, a new wire-like morphology of phenazine(Phz)-chloranilic acid(H2ca) cocrystal(PHC) is demonstrated for the first time, and the self-assembly of Phz and H2ca is controlled to selectively prepare kinetically stable wires and thermodynamically stable plates. Specifically, low precursor concentration is beneficial for one-dimensional(1D) self-assembly along the [010] crystallographic direction, while only supersaturation can trigger 2D self-assembly along the [100] and [010] directions, respectively. This is understandable in terms of the(020) face showing the largest attachment energy(Eatt) and the(002) face possessing the smallest surface energy(Esurf). Moreover, anisotropic Raman spectra related to the mode symmetry and atomic displacements in two types of PHCs are revealed, and the same Raman-active vibrational bands of PHC wire and plate show different polarization responses, which is intrinsically ascribed to their different molecular orientations.Overall, this is the first case that morphologies of cocrystal are precisely tuned with comprehensive investigations of their anisotropic vibrational characteristics.
