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Journal ArticleDOI

Charge transport processes in conducting polypyrrole/Prussian Blue bilayers

28 Jul 2002-Materials Chemistry and Physics (Elsevier)-Vol. 76, Iss: 1, pp 15-19
Abstract: The electronic transport properties of electrochemically deposited conducting polypyrrole (PPy)/Prussian Blue (PB) bilayer films have been studied by investigating the current–voltage (I–V) characteristics in dark and under white light illumination. The I–V characteristics observed are highly non-linear, both in dark and under illumination. Space charge limited conduction (SCLC) appears to be the dominant process governing the charge transport in such composite film structures which is also seen when these films are being used in photoelectrochemical or electrochromic mode. The sensitization effect appears due to relative ease of transport of the photogenerated carriers as compared the carrier transport in dark. more

Topics: Prussian blue (55%), Space charge (53%), Electrochromism (53%) more
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Abstract: The increase in the interaction between man and machine has made display devices indispensable for visual communication. The information which is to be communicated from a machine can be often in the form of color images. Electrochromic display device (ECD) is one of the most powerful candidate for this purpose and has various merits such as multicolor, high contrast, optical memory, and no visual dependence on viewing angle. A large number of electrochromic materials are available from almost all branches of synthetic chemistry. In this review, we have tried to describe the fundamentals of such electrochromic materials and their use in EDDs. The most important examples from major classes of electrochromic materials namely transition metal oxides, Prussian blue, phthalocyanines, viologens, fullerenes, dyes and conducting polymers (including gels) are described. Examples of their use in both prototype and commercial electrochromic devices are given. more

675 citations

Journal ArticleDOI
Stelian Lupu1, Cecilia Lete, Mariana Marin, Nicolae Totir  +1 moreInstitutions (1)
Abstract: New electrochemical sensors for dopamine (DA) and phenol derivative, based on hybrid inorganic redox material-organic conducting polymers, were developed. Hybrid inorganic–organic coatings based on Prussian blue, polyazulene, poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3-[(E)-2-azulene-1-yl)vinyl]thiophene) have been prepared by electrochemical methods in various configurations onto Pt substrate. Dopamine and 4-nitrophenol (4-NP) have been determined by square wave voltammetry using both mono and bilayer modified electrodes. The modified electrodes exhibited a linear response over wide range of 4-nitrophenol concentrations from 30 to 90 μM, with a detection limit of 8.23 μM (s/n = 3). A linear trend for the responses for dopamine concentrations ranging from 2 to 100 μM, with a sensitivity of 0.116 μA/μM, has been also obtained. more

111 citations

Journal ArticleDOI
Abstract: Preparation and electrochemical behaviour of bilayer films consisting of iron(III) hexacyanoferrate, well known as Prussian Blue, and of poly[4,4 ′ -bis(butylsulphanyl)-2,2 ′ -bithiophene], on a platinum electrode, are reported. The electrochemical features of the Prussian Blue/conducting polymer bilayer system are examined in aqueous and acetonitrile solutions. Cyclic voltammetric studies show that, in acetonitrile solvent, the inner layer Prussian Blue is electroactive to some extent, though the electrochemical response of the system is mainly accounted for by poly[4,4 ′ -bis(butylsulphanyl)-2,2 ′ -bithiophene] outer layer. On the other hand, in aqueous solution Prussian Blue exhibits good electroactivity. Under specific experimental conditions, the individual redox behaviour of each constituent of the bilayer is evidenced in the two solvents separately, i.e., that of PB and that of poly[4,4 ′ -bis(butylsulphanyl)-2,2 ′ -bithiophene] in aqueous and in organic solvent, respectively. However, interesting reciprocal influences are evident in the current/potential curves recorded under conditions which are discussed. more

54 citations


Journal ArticleDOI
17 Apr 2007-Nanotechnology
Abstract: Polypyrrole (PPy)/PB and PPy/Ag composite microtubes were synthesized in one pot by using methyl orange (MO) as a reactive self-degraded template. In contrast to reported conventional template approaches, the MO template did not need to be removed after polymerization. The formation mechanism, structural characteristics, conductivity, and electrochemical properties of the obtained PPy/PB and PPy/Ag microtubes are reported. more

50 citations

Journal ArticleDOI
Abstract: Expanded graphite filled polypyrrole (PPy/EG) conducting composites were prepared by in situ polymerization of pyrrole by the addition of expanded graphite in various proportions (0.25%, 0.50% and 1.0%). The synthesized samples were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), ultraviolet–visible absorption (UV–vis), X-ray diffraction (XRD) and electrical conductivity measurements. FTIR spectroscopy revealed the interaction between expanded graphite and polypyrrole (PPy). PPy/EG composites showed crystalline nature with rhombohedral structure. The band gaps of pure PPy and PPy/EG composites were determined by UV–vis absorption spectrophotometry and cyclic voltammetry. The electrical conductivities of the composites were enhanced dramatically to 110.04 S cm −1 compared to pure PPy. The composites also showed excellent electrochemical reversibility at the scan rate of 0.1 V s −1 and maximum reversible electrochemical response intaking charge capacity almost unchanged even up to 125th cycles. more

42 citations

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Journal ArticleDOI
Abstract: Highly stable organic electroluminescent devices based on vapor‐deposited Alq thin films have been achieved. The improvement in stability is derived from several factors including: (1) a multilayer thin‐film structure with a CuPc stabilized hole‐injection contact, (2) a hole‐transport diamine layer using a naphthyl‐substituted benzidine derivative, and (3) an ac drive wave form. These emissive devices have shown an operational half‐lifetime of about 4000 h from an initial luminance of 510 cd/m2. more

1,529 citations

01 Jan 1993-
Abstract: Preface. Electrical and electrochemical properties of ion conducting polymers. Electrical and electrochemical properties of electronically conducting polymers. Highly-conductive polymer electrolytes. Solvation mechanisms in low molecular weight polyethers. Lithium batteries with polymer electrodes. Lithium polymer batteries. Electrochromic devices. Laminated electrochromic displays and windows. Functionalized conductive polymer membranes/films. Electroactive polymers in chemical sensors. more

813 citations

Journal ArticleDOI
Ananth Dodabalapur1Institutions (1)
Abstract: Organic light emitting diode (LED) technology has reached a point where performance levels are adequate for a number of applications. This review examines the key scientific issues that underlie the operation of such LEDs. The most advanced LEDs are multilayer devices, with the different layers possessing specialized carrier transport/optical properties. A combination of these materials results in the highly efficient devices that have now been reported by several laboratories. The important issue of reliability and some possible applications for organic LEDs are surveyed. more

256 citations

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