Electrochemical impedance spectroscopy is used to identify a slow electron transport process in hydrogen evolution catalysed by amorphous molybdenum sulphides on glassy carbon. A new chemical synthesis leads to an amorphous molybdenum sulfide catalyst with a higher electronic conductivity.

Thermal conductivity of the Earth's lower mantle greatly impacts the mantle convection style and affects the heat conduction from the core to the mantle. Direct laboratory measurement of thermal conductivity of mantle minerals remains a technical challenge at the pressure-temperature (P-T) conditions relevant to the lower mantle, and previously estimated values are extrapolated from low P-T dat...

A study on charge transport properties of thin film Fe-doped SrTiO3 epitaxially grown on Nb-doped SrTiO3 is reported. Electric measurements between 350 °C and 750 °C show a transition from predominant ionic to electronic conduction and lower conductivity of the thin films compared to the bulk of polycrystalline samples. Defect chemical changes at elevated temperature were investigated by applyi...

Low-dimensional semiconductors are considered promising candidates for thermoelectric applications with enhanced performance because of a drastic reduction in their thermal conductivity, κl , and possibilities of enhanced power factors. This is also the case for traditionally poor thermoelectric materials such as silicon. This work presents atomistic simulations for the electronic, thermal, and...

Low-dimensional semiconductors are considered promising candidates for thermoelectric applications with enhanced performance because of a drastic reduction in their thermal conductivity, κl, and possibilities of enhanced power factors. This is also the case for traditionally poor thermoelectric materials such as silicon. This work presents atomistic simulations for the electronic, thermal, and ...

Self-assembled monolayers (SAMs) are widely used in a variety of emerging applications for surface modification of metals and oxides. Here, we demonstrate a new type of molecular self-assembly: the growth of organosilane SAMs at the surface of organic semiconductors. Remarkably, SAM growth results in a pronounced increase of the surface conductivity of organic materials, which can be very large...

In this paper, we systematically investigate three different routes of synthesizing 2% Na-doped PbTe after melting the elements: (i) quenching followed by hot-pressing (QH), (ii) annealing followed by hot-pressing, and (iii) quenching and annealing followed by hot-pressing. We found that the thermoelectric figure of merit, zT, strongly depends on the synthesis condition and that its value can b...

(Bi,Sr)FeO3-δ (BSF) cathode materials doped with either Co, Ni or Mn are synthesized by an ethylene diamine tetra-acetic acid (EDTA)-citrate complexing method, and the effects of the doping level on the mixed electronic-ionic conductivity at various temperatures are studied up to 800 °C. The phase purity and solid solution limit are investigated by X-ray diffraction (XRD). The ionic conductivit...

Modulation doping is a promising way to increase the electronic conductivity of thermoelectric materials and achieve high ZT figure of merit. In this work we provide a qualitative and quantitative comparison of the thermoelectric performance of a fieldeffect density modulated Si nanowire channel of diameter D=12nm versus its doped counterpart. We employ self-consistent atomistic tight-binding s...

We consider magnetic resonance electrical impedance tomography, which aims to reconstruct the conductivity distribution using the internal current density furnished by magnetic resonance imaging. We show the uniqueness of the conductivity reconstruction with one measurement imposing the Dirichlet boundary condition. And we propose a fast non-iterative numerical algorithm for the conductivity re...