Search results for "conductive polymer"

The Role of Emission Layer Morphology on the Enhanced Performance of Light-Emitting Diodes Based on Quantum Dot-Semiconducting Polymer Hybrids

2016

The influence of the morphology of quantum dot (QD)-semiconducting polymer hybrid emission layers on the performance of quantum dot-based light emitting diodes (QLEDs) is systematically investigated. Chemically grafted QD-semiconducting polymer hybrids are fabricated by the ligand exchange procedure between CdSe/CdxZn1−xS QDs and a new block copolymer consisting of a carbazole-based electroactive block with a low highest occupied molecular orbital level and a disulfide-based anchor block. The performance of QLEDs with hybrid emission layers is compared with QLEDs utilizing QD-only and physically mixed QD/polymer emission layers. It is shown that only in the emission layers formed by chemica…

An approach to the electrochemical activity of poly-(phenothiazines) by complementary electrochemical impedance spectroscopy and Vis–NIR spectroscopy

2010

Abstract The electroactivity of two poly-(phenothiazine), the poly-(Azure A) and the poly-(Methylene Blue), has been compared in this work. The spectroelectrochemical results prove clearly the existence of two electroactive moieties integrated in the polymeric lattice, the phenothiazine ring (detected by changes of absorbance at 590 and 685 nm) and the newly formed covalent links which fixes the monomers in the backbone of the polymer (detected by changes of absorbance at 460 and 875 nm). Differences in the electrochemical response of both polymers are due to differences in this covalent link. However in both polymers, the charge balance during electrochemical reactions takes place by the e…

Polymer-based symmetric electrochromic devices

1999

Abstract The fact that conjugated polymers repeatedly undergo electrochemical doping/undoping processes, which are accompained by color changes, makes these materials very attractive, and much effort has been devoted to their use in advanced devices. There is renewed interest in electroactive polymers that reversibly undergo both p- and n-doping because of their potential application in symmetric electrochemical devices. We employed fused molecules, dithienothiophenes, as monomers to obtain polymers with a narrow band gap suitable for n- and p-doping. The performance results of two symmetric electrochromic devices having as electrodes both poly(dithieno[3,4-b:3',4'-d]thiophene) (pDTT1) and …

Structural control of mixed ionic and electronic transport in conducting polymers

2016

Poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate), PEDOT:PSS, has been utilized for over two decades as a stable, solution-processable hole conductor. While its hole transport properties have been the subject of intense investigation, recent work has turned to PEDOT:PSS as a mixed ionic/electronic conductor in applications including bioelectronics, energy storage and management, and soft robotics. Conducting polymers can efficiently transport both holes and ions when sufficiently hydrated, however, little is known about the role of morphology on mixed conduction. Here, we show that bulk ionic and electronic mobilities are simultaneously affected by processing-induced change…

Bulk heterojunctions by boramers for plastic photovoltaics

2009

Functional Hybrid Materials Containing Polypyrrole and Polyoxometalate Clusters: Searching for High Conductivities and Specific Charges

2002

Composite Polymer Electrolytes with Improved Lithium Metal Electrode Interfacial Properties: I. Elechtrochemical Properties of Dry PEO‐LiX Systems

1998

Several types of lithium ion conducting polymer electrolytes have been synthesized by hot-pressing homogeneous mixtures of the components, namely, poly(ethylene oxide) (PEO) as the polymer matrix, lithium trifluoromethane sulfonate (LiCF{sub 3}SO{sub 3}), and lithium tetrafluoroborate (LiBF{sub 4}), respectively, as the lithium salt, and lithium gamma-aluminate {gamma}-LiAlO{sub 2}, as a ceramic filler. This preparation procedure avoids any step including liquids so that plasticizer-free, composite polymer electrolytes can be obtained. These electrolyte have enhanced electrochemical properties, such as an ionic conductivity of the order of 10{sup {minus}4} S/cm at 80--90 C and an anodic bre…

Light induced electropolymerization of poly(3,4-ethylenedioxythiophene) on niobium oxide

2010

Abstract The photoelectrochemical polymerization of poly(3,4-ethylenedioxythiophene), PEDOT, was successfully realized on anodic film grown to 50 V on magnetron sputtered niobium. Photocurrent Spectroscopy was employed to study the optical properties of Nb/Nb 2 O 5 /PEDOT/electrolyte interface in a large range of potential, and to get an estimate of the band gap and flat band potential of both the oxide and the polymer. Scanning Electron Microscopy was used to study the morphology of PEDOT. Both the optical and morphological features of the photoelectrochemically grown polymer were compared with those showed by PEDOT electropolymerized on gold conducting substrate.

Self-organized nanostructures of poly(4-vinylpyridine), polyaniline and polyamides due to metal complexation

2002

Comb-shaped supramolecules are constructed using flexible polymers and semi-rigid conjugated undoped or doped conjugated polymers upon complexing Zinc dodecyl benzene sulphonate, Zn(DBS) 2 . Self-organized nanostructures are formed in the bulk due to competing attractive interactions (coordination or water mediated hydrogen bonding) and repulsive polar/nonpolar interactions, showing characteristic long periods of ca. 30 A.

Electroactive polymeric material with condensed structure on the basis of magnesium(II) polyporphine

2011

International audience; Previous publication of the authors presented evidences that electroch emical oxidation of Mg(II) porphine (fully unsubstituted porphyrin, MgP) in acetonitrile (AN) at a very low potential leads to deposition of films at electrode surface corresponding to typical electroactive polymers, with their reversible transition betwee n the electronconducting and insulating states depending on the electrode potential/oxidation level ("film of type I"). It is demonstrated in the actual publication that these films in contact with a monomer-free solution are subject to an irreversible transformation to quite a different material ("film of type II") under the influence of a high…