Suchergebnisse

1 figure.-- Talk delivered at the HeteroNanoCarb-2019 Conference, Advances and applications in carbon related nanomaterials: From pure to doped structures including heteroatom layers, 2019, December 09th -- 13th, Centro de Ciencias de Benasque Pedro Pascual, in Benasque (Aragon, Spain). ; Poly(3-hexylthiophene) (P3HT) is one of the most popular conductive polymers for optoelectronic applications. [1] Their device operation critically depends on the nanocrystalline domain structure, i.e. the aggregate structure acquired by the polymer chains. Most common aggregates' distribution corresponds to H-aggregates, which implies charge transfer across the chains compared to those acquiring a J- aggregate structure with favorable charge transport along the chains. [2] We recently have shown that strong interactions between P3HT and water-dispersible graphene oxide can be obtained upon the formation of P3HT nanoparticles in aqueous dispersions. [3,4] These interactions enable a significant modification of the internal structure of P3HT aggregates towards a structure predominated by J-aggregates. Following this approach, in this work we have synthesized P3HT nanoparticles by the re-precipitation method in the presence of various types of water-soluble carbon nanostructures. Under scrutiny are graphene oxide flakes of different sizes, as well as nanocrystalline cellulose of type I and II. Of all the nanostructures exploited, the rarely investigated nanocyrstalline cellulose of type II, [5] exhibits significantly enhanced synergetic interface interactions with P3HT nanoparticles. This finding not only reveals a great potential towards improved thin film optoelectronic device structures, but even more underlines value of nanocellulose II for the development of green inks of photoactive polymers, ready to be used for printed electronics. ; Funding by EU (Project H2020-ITN 2014 642742), Spanish MINEICO (Project ENE2016-79282-C5-1-R1 (AEI/FEDER, UE), contract BES2017-080020 including FSE, UE, contract IJCI-2016-27789) and Government of Aragon (DGA-T03-17R and FEDER, UE).

4 figures.-- Supplementary information available. ; Graphene oxide (GO) is widely used as a component in thin film optoelectronic device structures for practical reasons because its electronic and optical properties can be controlled. Progress critically depends on elucidating the nanoscale electronic structure of GO. However, direct experimental access is challenging because of its disordered and nonconductive character. Here, we quantitatively mapped the nanoscopic charge distribution and charge dynamics of an individual GO sheet by using Kelvin probe force microscopy (KPFM). Charge domains are identified, presenting important charge interactions below distances of 20 nm. Charge dynamics with very long relaxation times of at least several hours and a logarithmic decay of the time correlation function are in excellent agreement with Monte Carlo simulations, revealing an universal hopping transport mechanism best described by Efros–Shklovskii's law. ; This research was financed by the Ministerio de Ciencia e Innovación and the Agencia Estatal de Investigación (MICINN/AEI, Spain) and associated Funds of the European Union through the projects "Nano and Meso Scales: Modelling, Structure and Characterization" (PID2019-104272RB-C52/AEI/10.13039/501100011033 and "Photoelectrochemical hydrogen production by optimized graphene-based interfaces" (PID2019-104272RB-C51/AEI/10.13039/501100011033) and the Fundación Séneca through the projects 19907/GERM/15 and 20860/PI/18, as well as the Gobierno de Aragón (Grupo Reconocido DGA-T03_20R). ; E.C. acknowledges funding of his predoctoral contract by Spanish MINEICO and associated European Social Funds (BES2017-080020). ; Peer reviewed