Charge and spin-dependent thermal efficiency of polythiophene molecular junction in presence of dephasing

The charge and spin-dependent thermoelectric properties of different lengths of polythiophene in a molecular junction are investigated using the B ¨uttiker probe method within Green function formalism in linear response regime. The coupling of the molecular chain to three-dimensional ferromagnetic electrodes is described by a tight-binding model for both parallel and antiparallel spin configurations. The decrease of height of transmission probability peaks and thermoelectric coefficients are observed in the presence of the B ¨uttiker probes. The reduction is more intensive in the strong dephased chains.Results show that the spin magnetothermopower is bigger than the charge magnetothermopower due to the larger difference between the spin thermopowers with respect to the charge ones. In addition, we observed that the kind of carriers participating in the thermoelectric transport depends on the number of the thiophene rings.

Preparation of Large-Scale Double-Side BDD Electrodes and Their Electrochemical Performances

Boron doped diamond(BDD)performs well in electrochemical oxidation for organic pollutants thanks to its wide electrochemical window and superior chemical stability.We presented a method to obtain well-adherent large-scale BDD/Nb electrode by the modified hot filament chemical vapor deposition system(HFCVD).SiC particles were sand blasted to enhance the adhesion of BDD coating.The BDD coating was then deposited on both sides of Nb which was placed vertically and closely with filament grids on both sides.The BDD/Nb electrodes had no deformation because the thermal deformations of the BDD films on both sides of the Nb substrate conteracted each other during cooling process after deposition.The surface morphology and purity of the BDD/Nb electrode were analyzed by Raman and scanning elestron microscope(SEM)techniques.Scratch test was used to investigate the adhesion of BDD films.The electrochemical performances were measured by cyclic voltammetry test.The BDD electrode at the B/C ratio of 2 000×10^(-6) held a higher oxygen evolution potential thanks to its high sp3 carbon content.Accelerated life test illustrated that the sandblasting pretreatment obviously enhanced the adhesion of BDD coating which resulted in a longer service duration than the un-sandblasted one.

Graphene-gold Nanoparticle Composite Film Modified Electrode for Determination of Trace Mercury in Environmental Water

The graphene-gold nanoparticles composite film modified glassy carbon electrode （EG- AuNPs/GCE） was prepared by one-step coelectrodeposition and employed for determination of trace mercury in environmental water with differential pulse stripping voltammetry. Such a nanostructured composite film combined with the advantages of gold nanoparticles and graphene, can greatly promote the electron-transfer process and increase accumulation abil-ity for Hg（Ⅱ）, leading to a remarkably improved sensitivity. The linear calibration curve ranged from 0.2 μg/L to 30 μg/L for Hg（Ⅱ） and the detection limit （S/N=3） was found to be 0.03 μg/L at a deposition time of 300 s. Moreover, the stablity of the as-prepared electrode and interferences from other substances were evaluated. The modified electrode was successfully applied to the direct detection of Hg（Ⅱ） in real water samples.

Direct Electron－transfer Reaction of Cytochrome C at a Bare Spectrographic Graphite Electrode

he electrochemistry of cytochrome C was investigated at a spectrographicgraphite electrode. In phosphate buffer solution (pH= 7. 0) , cytochrome C showedstable and quasi-reversible response. The formal potential E￣(o') was 0. 015 V (at25℃ , vs. SCE) and the heterogeneous electron transfer rate constant k_s obtainedvaried form 1. 10×10￣(-3) cm · s￣(-1) to 1. 80k×10￣(-3) cm · s￣(-1). The thermodynamic pa-rameters of the electron transfer reaction of cvtochrome C was also estimated. Fur-thermore, the effect of the various electrode surface states on the electrochemistryof cytochrome C was discussed.