Molecular n-type doping for air-stable electron transport in vacuum-processed n-channel organic transistors

The effects of n-type doping on the air-stability of vacuum-processed n-channel organic transistors have been investigated using perylene diimides and pyronin B as the active layer and dopant, respectively. Systematic studies on the influence of doping location revealed the n-type doping of bulk active layer or channel region significantly improves air-stability by compensating for the trapped electrons with the donated mobile electrons. Although n-type doping at the electrode contact could readily turn on the devices, it could not confer air-stable electron transport. The described approach would open up opportunities to enable and improve the stability of n-channel organic transistors in air.open23

Transistor performance of top rough surface of pentacene measured by laminated double insulated-gate supported on a poly(dimethylsiloxanes) base structure

We report the fabrication and electrical characterization of pentacene field-effect transistors with a laminated double insulated-gate using poly(dimethylsiloxanes) (PDMS) as their supporting structure. The ability of PDMS to conform to surfaces enables us to directly evaluate the device performance of the top rough surface of the pentacene active layer (the pentacene-air interface). The mobility measured for the top surface was only about 20% slightly lower than that of the bottom surface. Device stability under ambient conditions is evaluated. This device structure is useful for the characterization of electrical transport in both the top and bottom surface of a thin film simultaneously.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87784/2/033502_1.pd

Facile Synthesis of Nitrogen-doped Porous Carbon for Selective CO2 Capture

AbstractSolid-state post-combustion CO2 sorbents have certain advantages over traditional aqueous amine systems, including reduced regeneration energy since vaporization of liquid water is avoided, tunable pore morphology, and greater chemical variability. We report here an ordered mesoporous nitrogen-doped carbon made by the co- assembly of a modified-pyrrole and triblock copolymer through a soft-templating method, which is facile, economic, and fast compared to the hard-template approach. A high surface area mesoporous carbon was achieved, which is comparable to the silica counterpart. This porous carbon, with a Brunauer–Emmett–Teller (BET) specific surface area of 804.5 m2 g-1, exhibits large CO2 capacities (298K) of 1.0 and 3.1 mmol g-1 at 0.1 and 1bar, respectively, and excellent CO2/N2 selectivity of 51.4. The porous carbon can be fully regenerated solely by inert gas purging without heating. It is stable for multiple adsorption/desorption cycles without reduction in CO2 capacity. These desirable properties render the nitrogen-doped hierarchical porous carbon a promising material for post-combustion CO2 capture

The Meniscus-Guided Deposition of Semiconducting Polymers

The electronic devices that play a vital role in our daily life are primarily based on silicon and are thus rigid, opaque, and relatively heavy. However, new electronics relying on polymer semiconductors are opening up new application spaces like stretchable and self-healing sensors and devices, and these can facilitate the integration of such devices into our homes, our clothing, and even our bodies. While there has been tremendous interest in such technologies, the widespread adoption of these organic electronics requires low-cost manufacturing techniques. Fortunately, the realization of organic electronics can take inspiration from a technology developed since the beginning of the Common Era: printing. This review addresses the critical issues and considerations in the printing methods for organic electronics, outlines the fundamental fluid mechanics, polymer physics, and deposition parameters involved in the fabrication process, and provides future research directions for the next generation of printed polymer electronics

Synthesis of Polymer Dielectric Layers for Organic Thin Film Transistors via Surface-Initiated Ring-Opening Metathesis Polymerization

The use of surface-initiated ring-opening metathesis polymerization (SI-ROMP) for producing polymer dielectric layers is reported. Surface tethering of the catalyst to Au or Si/SiO_2 surfaces is accomplished via self-assembled monolayers of thiols or silanes containing reactive olefins. Subsequent SI-ROMP of norbornene can be conducted under mild conditions. Pentacene semiconducting layers and gold drain/source electrodes are deposited over these polymer dielectric films. The resulting field effect transistors display promising device characteristics, demonstrating for the first time that SI-ROMP can be used in the construction of organic thin-film electronic devices

Observation of orientation-dependent photovoltaic behaviors in aligned organic nanowires

We fabricated organic nanowire (NW) solar cells based on aligned NWs of n-channel organic semiconductor, N,N???-bis(2-phenylethyl)-perylene-3,4:9, 10-tetracarboxylic diimide via a filtration-and-transfer alignment method. It is well known that most efficient charge transport typically takes place along the long axis of organic NWs. However, there is no systematic study on the correlation between the orientation of NWs in the active layer and the power conversion efficiency (PCE) of solar cells. Our results demonstrate the effects of alignment direction of NWs on the PCE of organic solar cells with single-crystalline NWs.open0