Search results for "Volt"
showing 10 items of 2187 documents
Electrochemical and spectroscopic study on thiolation of polyaniline
2013
Abstract Polyaniline (PANI) is a conducting polymer, easily synthesized and lucrative for many electrochemical applications like ion-selective sensors and biosensors. Thiolated molecules, including biological ones, can be bound by nucleophilic attachment to the polyaniline backbone. These covalently bound thiols add functionality to PANI, but also cause changes in the electrochemical properties of PANI. Polyaniline studied in this work was electropolymerized on glassy carbon electrodes. 2-Mercaptoethanol (MCE) and 6-(ferrocenyl)hexanethiol (FCHT) were used as the thiols to form functionalized films. The films were characterized by cyclic voltammetry (CV), ex situ FTIR and Raman spectroscopi…
Organoboron Polymers for Photovoltaic Bulk Heterojunctions
2010
We report on the application of three-coordinate organoboron polymers, inherently strong electron acceptors, in flexible photovoltaic (PV) cells. Poly[(1,4-divinylenephenylene)(2,4,6-triisopropylphenylborane)] (PDB) has been blended with poly(3-hexylthiophene-2,5-diyl) (P3HT) to form a thin film bulk heterojunction (BHJ) on PET/ITO substrates. Morphology may be modulated to give a high percentage of domains (10-20 nm in size) allowing exciton separation. The photoelectric properties of the BHJs in devices with aluminium back electrodes were imaged by light beam induced current (LBIC) and light beam induced voltage (LBIV) techniques. Open circuit voltages, short circuit currents and overall …
Efficient, Cyanine Dye Based Bilayer Solar Cells
2012
Simple bilayer solar cells, using commercially available cationic cyanine dyes as donors and evaporated C60 layer as an acceptor are prepared. Cyanine dyes with absorption maxima of 578, 615 and 697 nm having either perchlorate or hexafluorophosphate counter-ions are evaluated. The perchlorate dye leads to cells with S-shape current-voltage curves; only the dyes with the hexafluorophosphate counter-ions lead to efficient solar cells. When the wide bandgap dyes are employed, S-shape current-voltage curves are obtained when the conductive polymer PEDOT:PSS is used as hole transport layer. Substitution of PEDOT:PSS with MoO3 leads to cells with more rectangular current–voltage curves and high …
Tailored conjugated polymer Langmuir-Schafer thin films in sensing transistors
2004
Organic Thin Film Transistors (OTFTs) have been fabricated, in a standard bottom gate configuration, with Langmuir-Schäfer (LS) or cast thin films of regioregular poly[1,4-(2,5-dioctyloxyphenylene)-2,5-thiophene], synthesized via an organometallic protocol, as active layers. The transistors electrical characterization has evidenced that LS based devices exhibit better performance level than cast film ones. Appealing perspectives for newly substituted conjugated polymers in OTFT sensing devices are discussed.
Ester-functionalized poly(3-alkylthiophene) copolymers : synthesis, physicochemical characterization and performance in bulk heterojunction organic s…
2013
Abstract The introduction of functional moieties in the donor polymer (side chains) offers a potential pathway toward selective modification of the nanomorphology of conjugated polymer:fullerene active layer blends applied in bulk heterojunction organic photovoltaics, pursuing morphology control and solar cell stability. For this purpose, two types of poly(3-alkylthiophene) random copolymers, incorporating different amounts (10/30/50%) of ester-functionalized side chains, were efficiently synthesized using the Rieke method. The solar cell performance of the functionalized copolymers was evaluated and compared to the pristine P3HT:PCBM system. It was observed that the physicochemical and opt…
Tuning Of Organic Heterojunction Conductivity By The Substituents' Electronic Effects In Phthalocyanines For Ambipolar Gas Sensors
2021
Abstract Exploiting organic heterojunction effects in electrical devices are an important strategy to improve the electrical conductivity, which can be utilized into improving the conductometric gas sensors performances. In this endeavor, the present article reports fabrication of organic heterostructures in a bilayer device configuration incorporating octa-substituted nickel phthalocyanines (NiPc) and radical lutetium bis-phthalocyanine (LuPc2) and investigates their sensing properties towards NH3 vapor. NiPc having hexyl sulfanyl, hexyl sulfonyl and p-carboxyphenoxy moieties are synthesized, which electronic effects are electron donating, accepting and moderate accepting, respectively, al…
Reactivity of Nickel(II) Porphyrins in oCVD Processes—Polymerisation, Intramolecular Cyclisation and Chlorination
2019
Abstract Oxidative chemical vapour deposition of (5,15‐diphenylporphyrinato)nickel(II) (NiDPP) with iron(III) chloride as oxidant yielded a conjugated poly(metalloporphyrin) as a highly coloured thin film, which is potentially useful for optoelectronic applications. This study clarified the reactive sites of the porphyrin monomer NiDPP by HRMS, UV/Vis/NIR spectroscopy, cyclic voltammetry and EPR spectroscopy in combination with quantum chemical calculations. Unsubstituted meso positions are essential for successful polymerisation, as demonstrated by varying the porphyrin meso substituent pattern from di‐ to tri‐ and tetraphenyl substitution. DFT calculations support the proposed radical oxi…
A Straightforward Electroactive π-Extended Tetrathiafulvalene (exTTF) Building Block
2012
The synthesis and X-ray structure of a new and readily available exTTF derivative (6) bearing a methyltriphenylphosphonium bromide moiety as a new building block for the construction of electroactive molecules is reported. The phosphonium salt 6, which was prepared in one step from 2-hydroxymethyl-exTTF as a stable yellow solid in 84 % yield, efficiently undergoes Wittig olefination reactions with a variety of aldehydes to predominantly form the E isomer. Electronic spectra and cyclic voltammetry of the novel compounds reveal the electronic communication between the electroactive units.
Electrochemical analysis of metallic heritage artefacts: voltammetry of microparticles (VMP)
2013
Abstract: This chapter discusses the application of the voltammetry of microparticles, a solid-state electrochemical technique, to the field of corrosion of archaeological metal. Identification of metals and alloys, identification, mapping and layer-by-layer analysis of corrosion products on metal surfaces using this technique are described. Applications include quantification of components of alloys and corrosion layers, and evaluation of metal conservation and the kinetics of long-term corrosion processes. Specific applications in archaeometry, conservation and restoration include authentication and dating.
Photovoltaic electricity scenario analysis in urban contests: an Italian case study
2012
Abstract This paper shows a methodology for the assessment of the photovoltaic potential in urban areas using Google Earth™ tool that provides either satellite images of the roofs of buildings or their number of floors by means of the Street View function. The applicability of the methodology has been tested on a selected urban area of the city of Palermo in the South of Italy. After classifying roofs according to the shape, orientation and pitch of buildings with different morphologies, the share of energy generated by the installable PV systems was evaluated with regard to the number of floors. Moreover the coverage of the electricity demand was investigated on the basis of the consumptio…