Semiconducting and insulating polymers and copolymers/Au nanograins based hybrid multilayers (HyMLs) were fabricated on p-Si single-crystal substrate by an iterative method that involves, respectively, Langmuir-Blodgett and spin-coating techniques (for the deposition of organic film) and sputtering technique (for the deposition of metal nanograins) to prepare Au/HyMLs/p-Si Schottky device. The electrical properties of the Au/HyMLs/p-Si Schottky device were investigated by current-voltage (I–V) measurements in the thickness range of 1-5 bilayers (BL).

At different number of layers, current-voltage (I–V) measurements were performed. Results showed a rectifying behavior. Junction parameters, such as barrier height (BH), from the I–V measurements for example for the PMMA-b-PS based Au/HyMLs/p-Si structure were obtained as 0.72±0.02 eV at 1BL and 0.64±0.02eV at 5BL. It was observed that the BH value of 0.61 eV obtained for the 5 BL PS based Au/HyMLs/p-Si structure was lower than the value of 0.68 eV of conventional Au/p-Si Schottky diodes. Thus, modification of the interfacial potential barrier for Au/p-Si diodes has been achieved using a thin MLs of different polymers based HyMls semiconductor.

Magnetic/fluorescent (magnetofluorescent) materials have become one of the most important tools in the imaging modality in vivo using magnetic resonance imaging (MRI) and fluorescence imaging. We succeeded in fabricating magnetofluorescent nanoparticles (MFNPs) consisting of silicon/magnetite composite nanoparticles. Our unique synthetic approach can control simultaneously the magnetic and fluorescence behaviors by varying the particle size, demonstrating the superparamagnetic behavior and green fluorescence for the MFNPs having mean diameter of 3.0 nm, and the ferromagnetic behavior without fluorescence for the MFNPs having mean diameter more than 5.0 nm. More intriguingly, the MFNPs with superparamagnetism can detect green fluorescence even after the magnetic guidance of MFNPs by the commercial neodymium magnet. Additionally, the MFNPs having two magnetic behaviors also possess good biocompatibility.

Electric transport in disordered media is usually explained in terms of different transport regimes, such as SCLC (Space Charge Limited Current) or TCLC (Trap Charge Limited Current) regimes. These models lead to exponential dependencies of the current on voltage, e.g., quadratic for SCLC or higher order for TCLC, with transition regions between them where fitting is poor. Alternatively, a statistical distribution in space and energy of the disordered traps, e.g., Gaussian or exponential, allows explaining transport in disordered materials. In this work, we propose a modeling based on the density of states (DOS) function, fitted from normalized differential conductivity curves obtained from experimental current-voltage curves. In general a Gaussian function is used for low energies whereas one or more exponential functions are used for higher energies. The proposed model is used to reproduce experimental current-voltage curves of organic nanocomposites, with gold and silver nanoparticles within chitosan matrixes. A unique expression is obtained for a very accurate fitting the experimental current-voltage characteristics in the whole voltage range without transition regions.

Developing advanced ionic electroactive devices such as ionic actuators and supercapacitors requires the understanding of charge drifting and diffusion processes, which depends on the distances over which the ions travel. The charge dynamics of Aquivion membrane actuators with EMI-Tf ionic liquid are investigated over a broad film thickness (d) range. A time domain charge dynamic method based on Poisson-Nernst-Planck relation is employed to evaluate the charge transport behaviors in the actuators. It is found that for the initial charging process the double layer time τDL is linearly proportional to the film thickness (d). However, for the later charging process under a high applied voltage (>0.5V ) where the substantial electromechanical reaction occurs, the charge transport behavior does not follow the d2 dependence as predicted by the random walk diffusion model. For comparison the charge dynamics of BMI-PF6 ionic liquid films without polymer was also investigated.

Magnetoelectric (ME) effects in bilayer composite cantilevers of magnetostrictive (MS) and piezoelectric (PE) materials on a substrate (Sub) are investigated theoretically for the FeCoBSi-AlN-Si system in open circuit mode and compared for different MS-PE-Sub layer thickness ratios and layer sequence choices. Static and resonant magnetic field excitations, the latter with resonance-enhanced cantilever oscillation, are investigated. Greatly differing behavior of the ME response with layer thicknesses is found for alternate layer sequences and excitation modes with the greatest resonant ME effect for the MS and PE layers on opposite sides of the substrate and the highest static effect for non-central substrates. The unexpected layer sequence systematics of the ME response are explained by the behaviour of the neutral (zero strain) plane in the strain coupled elastic layer stack.

Transport properties have been measured transverse to the plane of sheared and un-sheared thin-film nanocomposites of isotactic Polypropylene (iPP) and multiwall carbon nanotubes (MWCNTs) at various MWCNT concentrations. The sheared samples were processed in the melt at 200 0C at 1 Hz in a Linkan microscope shearing hot stage. The thermal and electrical conductivity measurements were performed on the same cell arrangement with the transport perpendicular to the thin-film plane using a DC method. The thermal and electrical conductivity perpendicular to the surface of the films are higher for the un-sheared as compared to the sheared samples. Interestingly, the percolation threshold appears smeared in both conductivity measurements likely due to pressing and shear treatment of the films, or the spacing between the data points. Important for electronics packaging and materials for which those anisotropic properties are highly desired this work presents important advances in understanding the structure-transport property relations.

Development of effective CO2 separation technologies is one of the most critical issues for implementation of CO2 Capture & Storage (CCS) because CO2 capturing covers about 60 % of the total CCS cost. CO2 capturing with solution absorption technology has gained current acceptance, and the actual operations have been demonstrated in many countries. However, This technology requires certain amount of energy in recovering CO2 from the CO2-capturing solution, which results in developing alternative CO2 capturing technologies. Because difference in partial pressure of the interest gas between feed and permeate side drives the separation, membrane separation does not need additional energy and can make CO2 separation much more effective. ☐In pre-combustion such as an integrated gasification combined cycle (IGCC) plant, CO2/H2 gas mixture after water-gas shift reaction has a pressure of 2.4 MPa, which would be preferable for membrane separation. Various membranes for CO2 separation over H2 have been investigated, however, the membrane separation has not been implemented due to lack in CO2 selectivity or permeability. In this paper, poly(amidoamine) (PAMAM) dendrimer is used to enhance affinity to CO2 and incorporated in a polymer matrix. The resulting polymeric membrane expressed excellent CO2 separation properties even under pressure. The CO2 permeance is relatively lower than the requirement value and 1.0 x 10-10 m3(STP)/(m2 s Pa). However, the permeance can be enhanced by reducing membrane thickness.