170,094 research outputs found
Synthesis of highly regioregular poly[3-(4-alkoxyphenyl)-thiophene]s by oxidative catalysis using copper complexes
No full textA novel, easy, and cost-effective synthetic procedure is reported for the production of very highly regioregular poly[3-(4-alkoxyphenyl)thiophene]s by means of oxidative coupling. Four copper complexes were synthesized and used as catalysts to obtain polymers with higher regioregularity compared to the previous oxidative coupling methodologies reported in the literature and similar to that obtained by McCullough and Rieke methods in the synthesis of poly-3-alkylthiophenes. The regioregularity of the synthesized polymers was investigated by UV-Visible characterization on polymer thin films and 1H NMR analysis. The remarkable potentialities of these polymers have emerged from field-effect transistor mobility measurements operated on devices with bottom-contact configuration and hexamethyldisilazane-treated SiO 2 gate dielectric, showing a well-defined p-type field-effect response and maximum mobility values in air higher than 10-4 cm 2 V-1 s-1. © 2013 Wiley Periodicals, Inc
High-efficiency standard and inverted polymer solar cells based on PBDTTT-C:[70]PCBM blend
No full textThe architecture of a polymer solar cell plays a crucial role on its stability because some of the materials used to build the device can suffer from degradation when exposed to air and/or oxygen. In this work we made a comparative study between the standard and the inverted polymer solar cells based on the bulk-heterojunction structure. We realized standard and inverted polymer solar cells using a blend film of poly[(4,8-bis-(2-ethylhexyloxy)- benzo[1,2-b;4,5-b′]dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl) -thieno[3,4-b]thiopene)-2,6-diyl] / [6,6]-phenyl C71 butyric acid methyl ester (PBDTTT-C:[70]PCBM) blend films. In the standard architecture, the transparent indium tin oxide (ITO) electrode is coated with poly-(3,4- ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) and used as a hole collecting electrode, while in an inverted device configuration, the ITO electrode is turned into the electron collecting contact by surface modification with zinc oxide (ZnO). The standard cells sequence is ITO/PEDOT:PSS/PBDTTT-C: [70]PCBM/Ca/Al and the inverted cells one is ITO/ZnO/PBDTTT-C:[70]PCBM/MoO 3/Ag. We studied the electrical behavior (by means of IV-dark and IV-light at different illumination levels and external quantum efficiency measurements) of both kinds of devices in order to investigate the influence of the architecture (standard vs inverted) on the performance of the solar cells
Optical properties of ionic liquid passivated CdSe/ZnS quantum dots dispersed in POC copolymer
No full textA new blue emitter oxadiazole/carbazole copolymer has been synthesized and combined with CdSe/ZnS quantum dots (QDs). Surface passivation of the QDs by ionic liquids was crucial to improve their compatibility with the polymer allowing the deposition of homogeneous nanocomposites films. The nanocomposites have been characterized by thermogravimetric analysis, infrared, UV-visible absorption, and photoluminescence spectroscopy. The emission spectra of nanocomposites show a wide spectrum from blue to orange wavelengths due to the combination of colors emitted by the polymer and QDs, respectively. © 2013 Society of Plastics Engineers
Il carme 45 di Catullo fra Terenzio e Orazio
No full textAbstract. A stylistic and linguistic study of c. 45 shows how much Catullus owes to Plautus’ and Terence’s palliata. At the same time the dialogue between Acmen and Septimius has some affinities with Horace’s c. 3,9, the contrast between Lydia and the poet
Catullo, Flavio e le deliciae inlepidae: il carme 6 del Liber
No full text: In Catullus’ c. 6 the poet addresses Flavius, a friend who is in love with an inlepida puella. A stylistic an linguistic study of the poem shows how, under a seemingly friendly manner, Catullus hides an ironic, perhaps sarcastic mode, while the feminine character could be even Lesbia
Rec. a M. C. J. Putnam, Artifices of Eternity. Horace's Fourth Book of Odes, Ithaca and London 1986
No full textRec. a AA.VV., Lecturae Plautinae Sarsinates XI. Mercator, a c. di R. RAFFAELLI e ALBA TONTINI Urbino (QuattroVenti) 2008
No full textPC70BM n-type Thin Film Transistors: Influence of HMDS Deposition Temperature on the Devices Properties
No full textThis study investigates the influence of the deposition temperature of hexamethyldisilazane (HMDS) on the performances of organic thin film transistors (OTFTs) using the [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM) as semiconductor. N-type OTFTs have been fabricated using this fullerene derivative, deposited from solution by drop casting technique on HMDS self-assembled monolayer (SAM) deposited at three different temperatures, 7 °C, 25 °C and 60 °C, in order to evaluate the influence of these deposition conditions on the morphology of PC70BM films and on the electrical responses of fullerene derivative-based OTFTs.The effect of the treatments of the surfaces was observed through contact angle measurements. AFM imaging of the deposited material has been used to analyse its structure and morphology. The transistors performances have been evaluated through I vs. V static characterization and parameters extraction.Contact angle vs. HMDS deposition temperature shows the minimum value at 60 °C, instead here field effect mobility presents a maximum. It has been observed that the lower hydrophobicity of the surface of the SAM induces the formation of more homogeneous surface of the PC70BM film, resulting in an increase of the OTFTs performances. © 2016 Elsevier Ltd
Eumelanin–PEDOT:PSS Complementing En Route to Mammalian-Pigment-Based Electrodes: Design and Fabrication of an ITO-Free Organic Light-Emitting Device
No full textThe growing interest toward biocompatible and bioinspired materials is boosting the investigation and the engineering of natural products as active components in electronic devices. The human pigment melanin, and particularly its subgroup composed by the eumelanins, the black-brown pigments derived from the oxidative polymerization of L-3,4-dihydroxyiphenylalanine (l-DOPA) via 5,6-dihydroxy-indole intermediates are increasingly emerging as valuable candidates for organic (bio)electronics applications. Capitalizing on a recently developed protocol to prepare high quality eumelanin coatings, this paper reports herein the design and the integration of standard commercial poly(3,4-ethylenedioxythiophene) with the poly(styrenesulfonate) (PEDOT:PSS) with eumelanin pigment. The new blend has made it possible to obtain a water stable quite transparent thin film, able to operate as an electrode for organic devices, complementing the PEDOT:PSS conductivity with the peculiar eumelanin properties, including adhesion, water stability, and ionic–electronic conductivity. As proof of concept, an unprecedented indium tin oxide-free organic light emitting diode implementing an eumelanin–PEDOT layer as the anode is fabricated and characterized. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei
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