Understanding Marangoni flow-driven solidification of polymer semiconducting films on an aqueous substrate

Marangoni flow-driven solidification of a polymer semiconducting film on an aqueous base media can be effectively controlled through spreading coefficient.

Field Optimization and Electrostatic Stress Reduction of Proposed Conductor Scheme for Pliable Gas-Insulated Transmission Lines

The implementation of stranded conductors in flexible gas-insulated transmission lines (FGILs) requires field intensity minimization as well as field irregularity suppression in order to avoid dielectric breakdown. Moreover, the interdependence of enclosure and conductor sizes of FGILs regarding electrostatic aspects necessitate critical consideration of their dimensional specifications. In this research, geometric and electrostatic field optimization for FGILs regarding stranded conductors is performed. In addition, the effect of conductor irregularity on field dispersion is analyzed, and a semiconducting film (SCF)-coated stranded conductor is proposed as a potential candidate for FGILs. Considering the performed optimized design, an 11 kV scaled-down model of a 132-kV FGIL was also fabricated in order to practically analyze its electrostatic and dielectric performances regarding simple and SCF-coated stranded conductors. Simulation and experimental investigations revealed that the SCF-coated stranded conductor significantly minimized the field irregularity of the FGIL along with improving in its dielectric breakdown characteristics.

Evidence for Photo-Switchable Carrier Mobilities in Blends of PbS Nanocrystals and Photochromic Dithienylcyclopentene Derivatives

We use derivatives of the photochromic molecule 1,2-bis(5′-carboxy-2′-methylthien-3′-yl)-cyclopentene in combination with semiconducting PbS nanocrystals to probe the feasibility of solid-state optical switching in hybrid nanostructured thin films. X-ray photoelectron spectroscopy is applied to differentiate between the different constituents in the blends, while field-effect transistor measurements in the dark reveal the effect of prior illumination with visible or ultra-violet light on the transport properties. By analyzing the response of the electric conductivity, the carrier concentration and mobility separately, we are able to distinguish between the effect of additional photo-excited charge carriers and photo-induced changes of the electronic structure of the semiconducting film. Our results suggest that coupling between the nanocrystals and the photochromic molecule is weak but also provide evidence that photochromism of the molecules may be partially preserved.

Highly stretchable polymer semiconductor films through the nanoconfinement effect

Soft and conformable wearable electronics require stretchable semiconductors, but existing ones typically sacrifice charge transport mobility to achieve stretchability. We explore a concept based on the nanoconfinement of polymers to substantially improve the stretchability of polymer semiconductors, without affecting charge transport mobility. The increased polymer chain dynamics under nanoconfinement significantly reduces the modulus of the conjugated polymer and largely delays the onset of crack formation under strain. As a result, our fabricated semiconducting film can be stretched up to 100% strain without affecting mobility, retaining values comparable to that of amorphous silicon. The fully stretchable transistors exhibit high biaxial stretchability with minimal change in on current even when poked with a sharp object. We demonstrate a skinlike finger-wearable driver for a light-emitting diode.