Summary: The electrochemical behaviour of four types of (phenylene ethynylene)‐alt‐(phenylene vinylene) hybrid polymers, 1 , 2 , 3 , and 4 have been investigated with respect to the influence of the grafted alkoxy side chains. In the case of the fully substituted polymers 2 , 3 , and 4 , the strong insulating nature of longer linear octadecyl or bulky branched 2‐ethylhexyl side chains lowers the HOMO levels of the polymers thereby increasing the discrepancy, ΔEg, between the electrochemical, Eequation/tex2gif-stack-1.gif, and the optical, Eequation/tex2gif-stack-2.gif, bandgap energies. Thus it is not possible to establish a direct correlation between the open circuit voltage, VOC, of bulk heterojunction solar cell devices of the configuration glass substrate/ITO/PEDOT:PSS/polymer 3 :PCBM(1:3, w/w)/LiF/Al and the HOMO energy levels of polymer 3 solely, as postulated in the literature. The photovoltaic (PV) parameters greatly depend on the grafted side chains.
Linear I–V curves of solar cell devices from polymers 3a – d , measured in the dark and under 100 mW · cm−2 solar simulator illumination. 相似文献
Phenol degradation was carried out in acidic aqueous solution on different crystal structures of PbO2 surfaces at room temperature. Phenol, benzoquinone and maleic acid concentrations were monitored during the electrolysis process. It was determined that β surfaces have higher performance than surfaces on phenol degradation. Then, the effect of crystallinities of pure β-PbO2 surfaces was investigated and found that higher crystallinity increased the efficiency of the phenol degradation process. 相似文献
The structure and the electrochemical oxidation reactions of polyaniline in an organic electrolyte are studied usingin-situ FTIR spectroscopy. In the first oxidation process a decrease of the N-H absorption band is observed, indicating a loss of hydrogen atoms. In the second oxidation step anion intercalation occurs. A broad absorption band at 4000 cm–1 is assigned to free carrier transitions in the conducting form of polyaniline. 相似文献
In this paper, CdS nanoparticles as a visible light active photocatalyst were coupled by NiFe2O4 and reduced graphene oxide (rGO) to form CdS–NiFe2O4/rGO nanocomposite by facile hydrothermal methods. The CdS–NiFe2O4/rGO nanocomposite shows enhanced photocatalytic activity for the degradation of methylene blue (MB) under visible light illumination. In addition to improved photocatalytic performance, this prepared nanocomposite shows increased photostability and is magnetically separable from the aqueous media. The degradation rate constant (kapp) of the optimized photocatalyst, i.e. CdS–NiFe2O4 (0.05)/rGO 25 wt% nanocomposite, was higher than the corresponding CdS and NiFe2O4 nanoparticles by factors of 11.1 and 8.9, respectively. The synergistic interactions between CdS, NiFe2O4 and rGO lead to enhanced surface area, reduced aggregation of the nanoparticles, decreased the recombination of photogenerated electron–hole pairs, and increased the charge separation efficiency and effective electron–hole generation transfer. According to the obtained results, a proposed mechanism of the photodegradation of MB under visible light irradiation is finally mentioned. 相似文献
1,2- and 1,3-Bis(trifluoroacetoxy) alcohols are easily obtained from the one-pot reaction of alkenes with phenyliodine(III) bis(trifluoroacetate) (PIFA) in the absence of any additive or catalyst. The products were converted into the corresponding diols by ammonolysis. The use of bicyclic alkenes has shown that rearranged 1,3-diacetoxy alcohols are mostly formed as the major products. 相似文献
Summary. A novel metal-free phthalocyanine and its nickel(II) and copper(II) phthalocyaninato complexes were prepared. The new compounds
were characterized by elemental analyses, 1H- and 13C-NMR, IR, UV-Vis, and mass spectral data. The NMR and/or UV-Vis spectra of these compounds showed extremely broad bands and/or
peaks. This phenomenon seems to be related to the presence of the sulfur substituents, which is consistent with the data observed
for similar compounds. The absorption spectra of these compounds were greatly affected by aggregation processes.
Corresponding author. E-mail: dismail@ktu.edu.tr
Received July 24, 2002; accepted August 2, 2002
Published online April 7, 2003 相似文献
The first total synthesis of (4E,6E)-1,7-bis(3,4-dihydroxyphenyl)-hepta-4,6-dien-3-one and an alternative synthesis of (4E,6E)-1,7-bis(4-hydroxyphenyl)-hepta-4,6-dien-3-one, two natural diarylheptanoids, mainly based on Claisen–Schmidt condensation were described. The crucial steps of the syntheses were the condensation of OH-protected 4-aryl-2-butanones with OH-protected 3-aryl-acrylaldehydes by the in situ enamination and then deprotection of OH groups to give the corresponding natural diarylheptanoids. 相似文献