Improved Anisotropic Thermoelectric Behavior of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) via Magnetophoresis

Abstract

There is strong demand for achieving morphological control of conducting polymers in its many potential applications, from energy harvesting to spintronics. Here, the static magnetic-field-induced alignment of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) particles is demonstrated. PEDOT:PSS thin films cast under modest mT-level magnetic fields exhibit a fourfold increase in the Seebeck coefficient and doubled electrical conductivity. Atomic force microscopy measurements confirm the presence of conducting islands that exhibit a 10-fold increase in the local charge carrier mobility and threshold behavior that is associated with phase separation. High-resolution scanning electron microscopy identifies a consistent structural coil-to-rod transition, and three-dimensional time-of-flight secondary-ion mass spectrometry imaging shows that the rodlike structures coincide with PEDOT domains that generally align with the magnetic field and cluster on the outer surface. Grazing-incidence small-angle X-ray scattering, Raman spectra, electron paramagnetic resonance, and circular dichroism spectroscopy point to the physical nature of the magnetophoretic alignment, which is expected to occur via magnetic coupling of PEDOT domains with polaron modes. Because casting under mT-level magnetic fields increases the electrical conductivity and Seebeck coefficient of PEDOT:PSS thin films without additional dopants that commonly limit the thermoelectric performance, our research reveals that low-field magnetophoresis significantly influences the structure and corresponding physical properties of PEDOT:PSS. Our results also point to concerns that the presence of small external magnetic fields in laboratory settings may appreciably and inadvertently influence the PEDOT:PSS morphology during settling, drying, or annealing processes.

High Thermoelectric and Flexible PEDOT/SWCNT/BC Nanoporous Films Derived from Aerogels

“…More importantly, BC with hydrophilic functional groups such as −OH and a high crystallinity can enhance the binding with conductive polymers and induce the ordered growth of PEDOT . The highly ordered PEDOT can provide a high electrical conductivity and Seebeck coefficient. , The PEDOT can be uniformly coated on the surface of the BC and forms a PEDOT/BC uniformly dispersed aqueous solvent suspension, which solves the insoluble and infusible problem of PEDOT. Given these properties, we consider BC as a promising matrix for manufacturing high-performance and flexible thermoelectric materials with low thermal conductivity and high electrical conductivity …”

Spatially Addressed Supramolecular Nanowires: A Full Structural Characterization by GIWAXS

“…Though, when only a few supramolecular nanowires are arranged in an electronic circuit, the scattering experiment becomes more complex because of the low signal intensity and device geometry. We reasoned that, in principle, these limitations can be overcome by using grazing-incidence wide-angle X-ray scattering (GIWAXS) as large areas within thin surficial layers are probed, with the advantage to elucidate the local molecular packing structure of the nanowires . Moreover, by measuring the sample in several directions, one can also potentially clarify the alignment and orientation of the polymer in their effective wiring configuration. , Finally, the coherence length of the supramolecular polymers may be obtained, and a GIWAXS-derived orientation parameter calculated .…”

Donor−acceptor−donor (D-A-D) structural monomers as donor materials in polymer solar cells: a DFT/TDDFT approach

“…Conjugated polymers have sparked significant interest in recent decades [ 12 , 13 ] due to their potential applications in fields such as organic field-effect transistors [ 14 ], organic light-emitting diodes [ 15 ], electrochromic devices [ 16 ], photovoltaics [ 17 ], electronic displays, supercapacitors, thermoelectric devices [ 18 ], and so on.…”