Achieving control over the morphology of conjugated polymer (CP) blends at nanoscale is crucial for enhancing their performances in diverse organic optoelectronic devices, including thin film transistors, photovoltaics, and light emitting diodes. However, the complex CP chemical structures and intramolecular interactions often make such control difficult to implement. We demonstrate here that cooperative combination of non-covalent interactions, including hydrogen bonding, coordination interactions, and π-π interactions, etc., can be used to effectively define the morphology of CP blend films, in particular being able to achieve accurate spatial arrangement of nanoparticles within CP nanostructures. Through UV-vis absorption spectroscopy and transmission electron microscopy, we show strong attachment of fullerene molecules, CdSe quantum dots, and iron oxide nanoparticles, onto well-defined CP nanofibers. The resulting core/shell hybrid nanofibers exhibit well-defined donor/acceptor interface when employed in photovoltaic devices, which also contributes to enhanced charge separation and transport. These findings provide a facile new methodology of improving CP/nanoparticle interfacial properties and controlling blend morphology. The generality of this methodology demonstrated in current studies points to a new way of designing hybrid materials based on organic polymers and inorganic nanoparticles towards applications in modern electronic devices.

Nanoparticles are often used for both metals and non-metals, in cosmetics, home appliances, electrical products, as well as paints and inks. Nanoparticles are commonly produced by the vapor phase method or the liquid phase method. However, it is still difficult to produce nanoparticles with complicated shapes, such as raspberry-shaped particles. In this study, we demonstrated that nano-raspberry particles can be made by coating the surface of the small- and the large-sized silica nanoparticle with a reactive, chemically adsorbed, monomolecular film and then by bonding the smaller nanoparticles to the surface of the larger nanoparticle. Furthermore, by preparing a fractal surface structure on a flat substrate surface, a super-water and oil repellent surface, which can potentially improve the application performance, was successfully produced.

Using palladium for hydrogen storage requires palladium (Pd) particles exhibiting specific parameters, including surface area, particle size, and particle shape, with increased interest in palladium nanoparticles (Pd NPs). In order to routinely monitor the synthesis of these particles a spectroscopic method is being developed using infrared (IR), Raman, and UV-Vis spectroscopy. By monitoring the production of Pd NPs, the growth of the NPs can be controlled to ensure quality of the product to match the desired finished particle specifications. For the reaction presented, the conversion of the intermediate tetraamminepalladium(II) chloride (PTC) to diamminepalladium(II) chloride (PDC) can influence the Pd NPs properties. This study is first being developed in lab bench scale quantities to allow ultimate control of the Pd NPs.

In-solution ligand exchange of PbSe QDs is used to examine the effect of capping ligand on the carrier density of PbSe QD films. Results show that carrier density can be modulated by a factor of 5 by choice of ligand without any additional post deposition treatments. Proper fabrication and measurement conditions for calculating carrier densities from C-V measurements using a sandwich structure on P-doped Si/SiO2/Al2O3/QD/Au structure capacitance devices are outlined. Combining carrier density results with field-effect-transistor measurements, promising ligands which display lower carrier densities without having a significant drop off in carrier mobility are identified as candidates for photodetection purposes.

Realization of the full potential of 2D nanosheet materials in energy storage and conversion devices requires heterogeneously structured electrodes having good electrical conductivity and large mean free paths for ion diffusion. Electrospinning of anisotropic objects usually obscures this anisotropy because of a large amount of carrier polymer typically required to form fibers. We demonstrate electrospinning of graphene with nearly quantitative retention of flake anisotropy to provide low to moderate density coatings of randomly oriented flakes having very large inter-flake mean free paths for ionic diffusion. Polyvinyl alcohol (PVA) is used as a carrier polymer and yields graphene anisotropy retention over an instability domain wherein electrospinning transitions to electrospraying. Graphene is deposited in polymer-encapsulated films at weight concentrations up to 50%, almost an order of magnitude higher than previously reported. Electrode applications will require at least partial replacement of PVA by electrically conducting polymers, and such polyelectrolytes should also suppress this electrospraying instability. We believe that large-scale electrospinning of graphene nanosheets will accelerate development of 2D materials in the fields of energy storage and conversion, catalysis, and tissue engineering.

We report 3D colloidal self-assembly (crystallization) of poly(ionic liquid) latexes to produce crystals that exhibit reversible melting and recrystallization in water, due to “classical” interparticle interactions, typical of multifunctional polymers. These new materials are derived from an ionic liquid monomer that is polymerized at room temperature by redox-initiated polymerization. Particle synthesis, self-assembly, thermal properties, and introductory light diffraction effects are reported with a focus on melting. These crystals are distinguishable from classical colloidal crystalline arrays, and are the first such crystals to exhibit thermal melting. This new hydrogel offers promise for engineering large volume production of photonic crystals active in the visible and proximal spectral regions, by crystallization from suspension (solution), characteristic of most useful chemical compounds.

The polymerization of 3,4-ethylenedioxythiophene (EDOT) onto nanosilica (SiO2) was synthesized in this study by using supercritical carbon dioxide (SCCO2). With the addition of dopants of p-toluenesulfonic acid (p-TSA) or decylbenzene sulfonic acid (DBSA), the PEDOT/SiO2 composite became conductive. The product was characterized by FTIR spectroscopy and the core-shell structure was confirmed through the TEM images. The electrical properties were analyzed by UV-vis absorbance and four-point probe measurement. DBSA is shown as the better dopants with the molar ratio (DBSA/EDOT) of 0.2 at the reaction time of 48 hours. The maximum coating percentage is 63 wt% under the optimal operation conditions at 40oC and 280 bar. The conductivity is tuned up to 6.6×10-2 S/cm after the coating process.

To improve the corrosion resistance and to increase the hardness of copper substrate in marine environment, the Cu-Ni/Ni-P composite coatings were prepared on the copper substrate using the galvanostatic electrolytic deposition method. The deposition current densities were explored to find the optimized deposition conditions for forming the composite coatings. Corrosion resistance properties were analyzed using the polarization curves and electrochemical impedance spectroscopy (EIS). Considering the corrosion resistance and hardness, the −20 mA/cm2 was selected to deposit Cu-Ni coatings on copper substrate and the −30 mA/cm2 was selected to deposit Ni-P coating on the Cu-Ni layer. The Cu-Ni/Ni-P composite coatings not only exhibited superior corrosion resistance compared to single Cu-Ni coating in 3.5 wt.% NaCl solution, but also showed much better mechanical properties than single Cu-Ni coating.

The study report on Vanadium dioxide thin films of about 100nm thickness deposited using pulsed laser deposition on Si (100). The novel phase change reported is attributed to the post-treatment of the films via ion implantation with 25 KeV C+ ion beam at varying particle fluence (1E15, 1E16, and 1E17 /cm2). At the initial fluence, the preferred phase is retained while amorphization and recrystallization of the film is observed as the fluence increase to 1E16 ions/cm2and 1E17 ions/cm2, respectively. The phase transition of the samples is observed to occur at a temperature below 320 K while stabilization of the low phase structure is observed for the middle fluence. Further increase restores the SMT behaviour/trend that occurred at elevated temperatures.