已为您找到该学者17条结果 成果回收站
封伟
,-0001,():
-1年11月30日
It is shown experimentally that the absorbance change observed in the ‘‘negative’’ time range, where probe pulse precedes pump pulse in real-time vibrational spectroscopy is induced only by the excited-state wave-packet motion as theoretically expected. Coherent molecular vibration of a polymer in the excited state was observed in the real-time trace without the effect of wave-packet motion in the ground state, which usually makes it difficult to ascribe the signal either to the ground state or to the excited state.
-
33浏览
-
0点赞
-
0收藏
-
0分享
-
215下载
-
0
-
引用
【期刊论文】Room Temperature Purification of Few-Walled Carbon nanotubes with High Yield
封伟
,-0001,():
-1年11月30日
Purification of high-quality few-walled carbon nanotubes (fWNTs) was developed by slow but selective oxidation in hydrogen peroxide (H2O2) at room temperature. The purity, nanotubes’ structure, and thermal stability of purified fWNTs were characterized by transmission electron microscopy (TEM), Raman spectroscopy, and thermogravimetric analysis (TGA), respectively. The results showed that fWNTs could be selectively purified by prolonging the stirring time in 30 wt % H2O2 solution. Highly purified fWNTs were obtained,having a high G/D ratio in Raman spectra and good thermal stability indicating the good quality of the purified fWNTs. The approach provides a simple low cost method for purification that also has higher nanotube yield than other purification methods.
-
44浏览
-
0点赞
-
0收藏
-
0分享
-
146下载
-
0
-
引用
封伟
,-0001,():
-1年11月30日
Organic photovoltaic devices based on a blend of poly(3-hexylthiophene) and a fullerene have been studied by inserting oriented zinc oxide nanopillars which were fabricated by a new method at low temperature (343 K). The dependence of the photovoltaic performance on the zinc oxide morphology was investigated, and it is concluded that the oriented zinc oxide nanopillar array plays an important role in collecting photogenerated electrons and acts as a conducting path to the electrode. Insertion of the oriented zinc oxide nanopillars in the photovoltaic cells produced enhanced performance with a power conversion efficiency of 1.22% under AM1.5 illumination.
-
49浏览
-
0点赞
-
0收藏
-
0分享
-
257下载
-
0
-
引用
封伟
,-0001,():
-1年11月30日
Flexible self-assembled membrane and hollow spheres (1.7–4.6 μm in diameter) accompanied with self-assembled membrane of poly(3,4- ethylenedioxythiophene) doped with acetic acid were synthesized in aqueous solution using ammonium persulfate as oxidant. Scanning electronic microscope imagines approved the flexible membrane and sphere-like morphologies and indicated a “grow from membrane” process. The mechanism of self-assemble phenomenonwas discussed by Fourier transform infrared and differential scanning calorimeter. Itwas found that self-assembly was driven by the hydrogen bond between 3,4-ethylenedioxythiophene monomers and acetic acid. The concentration of acetic acid plays an essential role in the self-assemble process. Moreover, the electrochemical properties of them with different morphologies were also characterized by cyclic voltammetry.
-
82浏览
-
0点赞
-
0收藏
-
0分享
-
366下载
-
0
-
引用
封伟
,-0001,():
-1年11月30日
Multiwalled carbon nanotubes (MWCNTs) were grafted by chitosan (CS); the product could disperse well in poly(vinyl alcohol) (PVA) aqueous solution with 2% (v/v) acetic acid solution.Because this product has potential in several biological fields, it was electrospun so as to enlarge the surface area. Raman spectra indicated that the electrospinning process did not severely alter the electron hybridization of carbon atoms within the nanotube framework. Moreover and interestingly, these nanofibers showed a novel sheath–core structure; the outer and inner diameters of these sheath–core nanofibers were about 200 nm and 100 nm,respectively. These nanofibers’ electrochemical properties were characterized by detection of hydrogen peroxide and voltammetric responses of potassium ferricyanide. The electrospun fibers’ web displayed faster electron transfer kinetics and better electrochemical properties than its cast film, which justified further applications in biological areas.
-
48浏览
-
0点赞
-
0收藏
-
0分享
-
591下载
-
0
-
引用