73 research outputs found
In−situ monitoring Poly(3-hexylthiophene) nanowire formation and shape evolution in solution via small angle neutron scattering
The crystallization of poly(3-hexylthiophene) (P3HT) to form nanowires has attracted considerable interest because this process significantly increases the hole mobility when compared to amorphous P3HT, leading to improved performance in photovoltaic and other organic electronic devices. However, full characterization of the crystallization self-assembly of the polymer chains in solution has not been achieved yet, due to limited use of not destructive techniques. Here, we investigate the ageing-driven formation and evolution of regioregular (rr) P3HT nanostructures in chlorobenzene solution using small angle neutron scattering (SANS) and UV–Vis spectroscopy. We have monitored how the shape of the rr-P3HT aggregates evolves. The initial states for rr-P3HT chains are the random coils, which straighten to form rods. These subsequently π - π stack to form 2D lamellae, which further stack to create nanowires. The formation of nanowires is promoted both by the length of ageing and by low temperatures (). Temperatures above reverse the formation of nanowires. Additionally, atomic force microscopy (AFM) and grazing incidence wide angle x-ray scattering (GIWAXS) reveal that the nanowires can be successfully aligned during deposition by off-axis spin coating. Finally, the anisotropic conductivity of the aligned rr-P3HT nanowire films is reported. This is significant for applications such as gas sensing or organic thin film transistors, where increased conductivity and controlled nanostructure are desirable
The Emission of Electromagnetic Radiation from Charges Accelerated by Gravitational Waves and its Astrophysical Implications
We provide calculations and theoretical arguments supporting the emission of
electromagnetic radiation from charged particles accelerated by gravitational
waves (GWs). These waves have significant indirect evidence to support their
existence, yet they interact weakly with ordinary matter. We show that the
induced oscillations of charged particles interacting with a GW, which lead to
the emission of electromagnetic radiation, will also result in wave
attenuation. These ideas are supported by a small body of literature, as well
as additional arguments for particle acceleration based on GW memory effects.
We derive order of magnitude power calculations for various initial charge
distributions accelerated by GWs. The resulting power emission is extremely
small for all but very strong GWs interacting with large quantities of charge.
If the results here are confirmed and supplemented, significant consequences
such as attenuation of early universe GWs could result. Additionally, this
effect could extend GW detection techniques into the electromagnetic regime.
These explorations are worthy of study to determine the presence of such
radiation, as it is extremely important to refine our theoretical framework in
an era of active GW astrophysics.Comment: Appears in Gravitational Wave Astrophysics, Editor C.F. Sopuerta,
Astrophysics and Space Science Proceedings, Volume 40. ISBN
978-3-319-10487-4. Springer International Publishing Switzerland, 2015, p.
30
Tracing aquatic food webs using fatty acids: from qualitative indicators to quantitative determination
Quality Changes in Tomatoes and Resistance to Alternaria Infection as Influenced by Varying Storage Temperature
Distribution of Protein, Lycopene and the Elements Ca, Mg, P and N Among Various Fractions of Tomato Juice
Silver ions inhibit the ethylene-stimulated production of ripening-related mRNAs in tomato
- …