C8‐BTBT‐C8 Thin‐Film Transistors Based on Micro‐Contact Printed PEDOT:PSS/MWCNT Electrodes

Advances in organic materials manufacturing have enabled the creation of electronic devices using solution‐processing techniques by employing soluble materials with high conductivity grade. In this exploratory study, the use of micro‐contact for poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymer ink deposition as high‐quality structured electrodes for organic field‐effect transistors (OFETs) in top‐contact geometry is demonstrated. The optimized OFET's solution‐processed fabrication is a promising strategy to be realized in the simple, cost‐effective roll‐to‐roll manufacturing processes. The electrical performance of the fabricated devices is comparable to transistors with gold electrodes prepared via vacuum deposition, and even exceeding the values of the charge carriers’ mobilities and featuring lower contact resistance (Rc), due to lower charge‐carrier injection barrier for carbon‐based organic electrodes. An addition of multi‐walled carbon nanotubes to the PEDOT:PSS decreases Rc even further, changing the work function for better energy alignment with semiconductor materials

Biogeochemical patterns of created riparian wetlands: Tenth-year results (2003)

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Spectral modelling of the "Super-Chandra" Type Ia SN 2009dc - testing a 2 M_sun white dwarf explosion model and alternatives

Extremely luminous, super-Chandrasekhar (SC) Type Ia Supernovae (SNe Ia) are as yet an unexplained phenomenon. We analyse a well-observed SN of this class, SN 2009dc, by modelling its photospheric spectra with a spectral synthesis code, using the technique of 'Abundance Tomography'. We present spectral models based on different density profiles, corresponding to different explosion scenarios, and discuss their consistency. First, we use a density structure of a simulated explosion of a 2 M_sun rotating C-O white dwarf (WD), which is often proposed as a possibility to explain SC SNe Ia. Then, we test a density profile empirically inferred from the evolution of line velocities (blueshifts). This model may be interpreted as a core-collapse SN with an ejecta mass ~ 3 M_sun. Finally, we calculate spectra assuming an interaction scenario. In such a scenario, SN 2009dc would be a standard WD explosion with a normal intrinsic luminosity, and this luminosity would be augmented by interaction of the ejecta with a H-/He-poor circumstellar medium. We find that no model tested easily explains SN 2009dc. With the 2 M_sun WD model, our abundance analysis predicts small amounts of burning products in the intermediate-/high-velocity ejecta (v > 9000 km/s). However, in the original explosion simulations, where the nuclear energy release per unit mass is large, burned material is present at high v. This contradiction can only be resolved if asymmetries strongly affect the radiative transfer or if C-O WDs with masses significantly above 2 M_sun exist. In a core-collapse scenario, low velocities of Fe-group elements are expected, but the abundance stratification in SN 2009dc seems 'SN Ia-like'. The interaction-based model looks promising, and we have some speculations on possible progenitor configurations. However, radiation-hydro simulations will be needed to judge whether this scenario is realistic at all.Comment: 22 pages, 12 figures, published in MNRAS. V2: several small corrections (typos, style