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[en] Electron paramagnetic resonance experiments were performed on [CH(SO3)y]x samples in three doping levels, y=0.008, 0.09 and 0.20. Observed are single Dysonian signals with g=2.001 ± 0.001 and asymmetry increasing for the dopant concentration and the temperature(T) increase. The Curie-type paramagnetism is observed in the y=0.008 sample, and the Pauli in the y=0.09 and 0.20 samples. The EPR linewidths, whose typical values at room-temperature and 1 Atm. are 0.6 to 0.8 G, get broadened as T decreases. But, it becomes nearly constant below 170 K for the y=0.09 sample, and it even starts to decrease around 210 K for the y=0.20 sample. Also reported is the linewidth change due to the environmental gas pressure at the temperatures where the T-dependent linewidth decreases as T increases. The anomalous linewidth change by T as well as the sensitive change by the pressure is unique in the SO3-doped (CH)x among numerous (CH)x derivatives. (Author)
[en] The aryl-fused TTF's, Δ2,Δ''-bis-(acenaphtho [1, 2, d]-1, 3-dithiolidene) and Δ2,Δ''-bis-(phenanthro [9, 10, d]-1, 3-dithiolidene) have been synthesized in order to test the suggestion of Little that these compounds might form charge transfer complexes with electron acceptors to serve as the model compounds for the study of excitonic mechanism of superconductivity. The syntheses are described in detail
[en] The data on the synthesis and properties of furazan derivatives fused with pyridine, pyran, thiopyran, azepine and thiepine rings are surveyed and described systematically. The bibliography includes 85 references.
[en] The electrochemical behaviour of 5-(nitrophenyl)-1,2-dithiole-3-thiones and 5-(nitrophenyl)-1,2-dithiole-3-ones was studied by cyclic voltammetry in DMF. The standard reduction potentials of 5-(p-nitrophenyl)-dithiolethione and 5-(p-nitrophenyl)-dithiolone entered into a linear correlation involving standard reduction potentials of substituted nitrobenzenes and known electronic constants of several substituents. This correlation allowed the determination of the electronic effects of [3-thioxo-1,2-dithiole]-5-yl and [3-oxo-1,2-diothiole]-5-yl groups which were, respectively, σp-=1.14 and σp-=0.86, comparable with those of nitro or cyano substituents
[en] The development of new polymers-based for application in plastic solar cells is attracting much research interest for their potential as a low-cost system for renewable energy generation. We report herewith a comparative study on three donor-acceptor carbazole-based copolymers containing thieno thiophene moieties for application in organic photovoltaic (OPV) devices. The polymers were synthesised by Suzuki cross coupling, in order to investigate its suitability to enhance the polymer properties in photovoltaic cell. Morphological, spectroscopic and charge-transport measurements are used to investigate the influence of either the thieno thiophene moieties on the structure and photophysical properties of the copolymer rationalise the solar cell characteristics. The optical band gap, E_g of polymers P1, P2 and P3 were 2.46 eV, 2.36 eV and 2.47 eV respectively. The photophysical properties of these polymers show that P2 has the narrowest optical band gap due to the electrostatic interaction between the hydrogens at the 4-position on thieno thiophene rings and the fluorine substituents on the neighbouring carbazole repeat units. These results are in agreement with the design procedures for the use of these materials in photovoltaic applications. We tentatively explain such differences on the basis of reduced molar absorbance and reduced charge-carrier mobility in the thieno thiophene-based polymers. (author)