Papers by Keyword: Conjugated Polymer

Abstract: The purpose of this study is to evaluate the thermal degradation of hybridize doped poly(dioctylfluorene) (PF8) film with polydimethylsiloxane (PDMS). The hybridized PF8/PDMS films were produced using solvent casting technique. The poly(dioctylfluorene) was dissolved using chloroform and subsequently polydimethylsiloxane was added prior mixing. Three different concentrations of PF8 were used to prepare the doped film. After casting, the samples were put in an oven at 100°C for 5 minutes for curing process. Later the thermal degradation test was conducted on the prepared sample for the duration of 1 hour, 2 hours, 3 hours and 24 hours to observe the effect of temperature on the photoluminescence properties of PF8. UV-visible spectroscopy was mainly used to measure the absorption intensity of the hybridized materials. It was configured that the optimum doped concentration for PF8 with PDMS is by using 5.0×10^-3 mol of PF8. This is due to a good solubility of PF8 and easy to be casted.

Abstract: Due to the difficulty in the selective synthesis of semiconductor (s-) and metal (m-) single-walled carbon nanotubes (SWCNTs), we still need to explore the selective extraction technology of s-SWCNTs. Using Poly[9-(1-octylonoyl)-9H-carbazole-2,7-diyl] (PCz) extraction of s-SWCNTs has attracted extensive attention in recent years, because it can selective extraction of large-diameter s-SWCNTs with high purity. However, influence of the molecular weight of this polymer on the s-SWCNTs selective extraction properties remains unclear. In this study, we used PCz with different average molecular weights to study the ability of selective extraction s-SWCNTs from pristine arc discharge carbon nanotubes. Spectra studies indicate that compared to the PCz with lower molecular weight, the PCz with higher molecular weight has better selective extraction ability, and can help to obtain s-SWCNTs with higher purity (>99%) and high yield. FETs devices have been prepared by s-SWCNTs obtained via PCz with higher molecular weight exhibit higher on/off ratio, lower off current and lower subthreshold swing. This work offers a reference of the design and synthesis of PCz polymer that performs sufficient selective ability in extracting s-SWCNTs with promising applications.

Abstract: The purpose of this work was to develop efficient ionochromic polydiacetylenes for lead ion (Pb²⁺) detection. The method developed used co-assemblies of polydiacetylene and anionic surfactant. The co-assemblies were prepared by mixing 10,12-pentacosadiynoic acid (PCDA) with sodium dodecyl sulphate (SDS) and subsequent UV irradiation-polymerization. The effects of mole ratio of PCDA to SDS, detection limit and stability were investigated. A color transition of poly(PCDA/SDS) co-assemblies with Pb²⁺ from blue to red was directly observed without the use of any technological equipment. However, Ni²⁺ and Fe³⁺ were non-responsive. The co-assemblies of poly(PCDA/SDS) showed rapid ionochromic response and selectivity to Pb²⁺ in aqueous solution. Based on this approach, the reagent has many advantages such as simple preparation, low cost, low chemical consumption and fast analysis. It is an alternative method for the development if sensing material for the detection of metal ions contaminating the environment.

Abstract: An organic nanocomposites, based on a conjugated polymer (MEH-PPV) as electron donor material and carbon nanopearls (CNPs) as electron acceptor material, have been elaborated and optoelectronically studied. The effect of CNPs concentration on the electric and photoelectric properties in these blends has been investigated. Dielectric measurements demonstrate that the blend conductivity displays a dramatic increase, reaching 0.6 S/m for a CNPs concentration about 1 wt.%. The elaborated organic nanocomposites were used as photoactive materials in organic solar cells.

Abstract: In this paper, we reported one vinylfluorene derivative 9,9-dihexyl-vinylfluorene and its corresponding polymers. The monomer and polymers were characterized by NMR, UV-Vis, PL and Gel Permeation Chromatography (GPC). Compared with the monomer, the polymers showed blue-shift in UV-Vis spectra but red-shift in PL spedtra. This kind of side-chain polyfluorenes could be candidates of blue OLED, organic solar cells, and so on.

Abstract: In the article we present a unique analytical tool for the characterization of conjugated polymers – SEC-DAD (Size Exclusion Chromatography – Diode Array Detector). The chromatographic separation is performed in a conventional SEC mode which provides narrow molecular-weight fractions of the analyzed polymer. The uniqueness of the SEC-DAD combination comes out with the utilization of DAD for the monitoring the absorption characteristics of particular fractions along the molecular weight distribution. If applied in the characterization of the conjugated polymers, SEC-DAD helps to reveal the dependencies of (i) the extent of conjugation and (ii) covalent and configuration structure of the polymer on the molecular weight.

Abstract: Conjugated polymers have been widely used for electronic purpose applications due to their numerous advantages. This has led many researches to pay their major attention in studying on characteristics of conjugated polymer thin films. The purpose of this study was to investigate the effect of undoped conjugated polymer thin films on their optical and electrical properties. Poly(3-thiophene acetic acid), Polypyrrole and Polythiophene thin film was fabricated on ITO glass substrate by using EIS. Film thickness, energy band gap and electrical conductivity of thin films were characterized by using profilometer, ultraviolet-visible spectrometer and four point probe method respectively. The thickness of each thin film varied between 50.534 nm to 97.03 nm. The result has shown that thicker film has lower energy band gap compared to the thinner one. However the electrical conductivity showed an opposite behavior.

Abstract: In this research, the microspheres of poly (99-dihexylfluorene) were fabricated with dichloromethane as a good solvent by self-assembly methods. The effects of poor solvent vapor, polymer concentration, and the temperature of environment on the formation of the sphere patterns were investigated. It was found that the microsphere could be easily prepared in the ethanol non-solvent vapor atmosphere. Besides, increasing the environment temperatures was advantageous to fabricate microspheres. Furthermore, the property of non-solvent vapor was a key role to the formation of the sphere.

Abstract: because of organic solar materials with light weight, low cost, flexible, which widespread concern by the people. According to main chain structure of polymer donator material classification, the article summarized the progress of research in this area in recent years and a detailed introduction by some attention from materials, design, performance analysis to device fabrication and performance, and provides valuable reference for future materials research and development.

Abstract: Field dependent polaron transport in a conjugated polymer chain is studied numerically with local thermal fluctuations taken into account. Within a dynamical evolution method, a polaron moves from the left to the right side of the polymer chain in the presence of an applied electric field. Local lattice fluctuations are assumed to occur in a random way. The local thermal fluctuations are found to be equivalent to a potential barrier for the polaron. The range of the thermally disturbed region in the molecule and the effective temperature difference resulted from asymmetric thermal absorptions determine the height of the barrier. The intra-molecule polaron mobility obeys a logarithmic law in low electric field range provided that there exist asymmetric thermal absorptions within the molecule.