Alkyl Thiophene Research Articles

D-π-A Structured ZnII-Porphyrin Dyes with Thiophene Moiety for Highly Efficient Dye-Sensitized Solar Cells

A dye that does it! Zinc porphyrins enveloped with long alkyl thiophene units and a simply structured organic co-adsorbent are presented. Dye-sensitized solar cells prepared using this new dye show an enhanced performance.

Highly Efficient Inverted Organic Solar Cells Through Material and Interfacial Engineering of Indacenodithieno[3,2‐b]thiophene‐Based Polymers and Devices

A synergistic approach combining new material design and interfacial engineering of devices is adopted to produce high efficiency inverted solar cells. Two new polymers, based on an indacenodithieno[3,2‐b]thiophene‐difluorobenzothiadiazole (PIDTT‐DFBT) donor–acceptor (D–A) polymer, are produced by incorporating either an alkyl thiophene (PIDTT‐DFBT‐T) or alkyl thieno[3,2‐b]thiophene (PIDTT‐DFBT‐TT) π‐bridge as spacer. Although the PIDTT‐DFBT‐TT polymer exhibits decreased absorption at longer wavelengths and increased absorption at higher energy wavelengths, it shows higher power conversion efficiencies in devices. In contrast, the thiophene bridged PIDTT‐DFBT‐T shows a similar change in its absorption spectrum, but its low molecular weight leads to reduced hole mobilities and performance in photovoltaic cells. Inverted solar cells based on PIDTT‐DFBT‐TT are explored by modifying the electron‐transporting ZnO layer with a fullerene self‐assembled monolayer and the MoO3 hole‐transporting layer with graphene oxide. This leads to power conversion efficiencies as high as 7.3% in inverted cells. PIDTT‐DFBT‐TT's characteristic strong short wavelength absorption and high efficiency suggests it is a good candidate as a wide band gap material for tandem solar cells.

Entropic effects in carbon nanotubes-templated crystallization of Poly(3-alkyl thiophenes, P3HT, P3OT)

A significant increase in polymer crystallinity is reported in composites of carbon-nanotubes (CNT) and Poly(3-octylthiophene-2,5-diyl), P3HT and Poly(3-octylthiophene-2,5-diyl), P3OT; Differential scanning calorimetry (DSC) reveal an increase from about 40% crystallinity of the native P3HT to ∼62% in composites containing 25 wt% MWNT. A similar behavior is observed in P3OT with ∼68% crystallinity, a double crystallization peak and higher melting temperature than the native polymers. The effect is unique to CNT and is not induced by fullerenes or graphene layers. High-resolution transmission electron microscopy, (HRTEM) of CNT-polymer dispersions reveal chains stacked upon the CNT in an elongated, stretched conformation. Following a detailed molecular study by Bernardi et al. and the HRTEM observations the DSC results are attributed to a CNT-mediated entropic effect: due to their intrinsic, 1D cylindrical shape the CNT impose an increased conjugation length on chains adsorbed and stacked upon dispersed CNT. Crystallization thus commences from a heterogeneous mixture of native chains and chains with a longer persistence length (higher effective rigidity) and consequentially a lower effective height of the entropic barrier for crystallization. The findings offer a new insight into the origins of CNT-induced polymer nucleation.

Growth of Polythiophene/Perylene Tetracarboxydiimide Donor/Acceptor Shish-Kebab Nanostructures by Coupled Crystal Modification

Self-assembled crystalline organic nanostructures containing electron donor and acceptor materials hold promise as building blocks for photovoltaic devices. We show that coupled crystallization of poly(3-hexyl thiophene) (P3HT) and perylene tetracarboxydiimide (PDI) induced by solvent evaporation, wherein both components modify crystallization of the other, gives rise to donor/acceptor "shish-kebabs" with tunable nanostructures. P3HT kinetically stabilizes supersaturated solutions of PDI and modifies the growth of PDI crystals, leading to formation of extended PDI shish nanowires that in turn serve as heterogeneous nucleation sites for fibrillar P3HT kebabs during solvent casting. The dimensions of these nanostructures can be tailored through variations in donor/acceptor ratio or solvent quality, and the method is shown to be general to several other poly(3-alkyl thiophenes) and perylene derivatives, thus providing a simple and robust route to form highly crystalline nanophase separated organic donor/acceptor assemblies.

Simultaneous removal of sulphide and nickel by the compound of Chitosan Schiff Base from crude oil under microwave irradiation

A study has been carried out for simultaneous desulfurization and demetalization by electric desalting from crude oil based on the oxidation of alkyl thiophene and nickel compounds with the compound of Chitosan Schiff Base under the condition of microwave irradiation (SDDM). Besides, an investigation has been made about the influence of Chitosan Schiff Base compound dose, initial temperature, and microwave time on desulfurization and demetalization. By using the optimized conditions for SDDM, up to 56% of sulfur and 82% of nickel removal rates were achieved for model compounds in crude oil samples. With the same conditions but without microwave the removal efficiency was lower than 56% for sulfur model compound and than 82% for nickel porphyrin in crude oil samples. Additionally, in order to develop a fundamental understanding of the SDDM mechanism of sulfides, a molecular simulation of sulfur compounds was performed with both the Hartree–Fock (HF) and second-order Moller–Plesset (MP2) levels of theory for the calculation of reaction kinetic rate by using Gaussian 03 program package. In comparison with conventional desulfurization and demetalization technology, the proposed SDDM process can accomplish the simultaneous removal of sulfur and nickel compounds from crude oil under relatively mild conditions.

Random copolymers consisting of dithienylcyclopentadienone, thiophene and benzothiadiazole for bulk heterojunction solar cells

Novel random copolymers containing dithienylcyclopentadienone, thiophene and benzothiadiazole were synthesized and photovoltaic properties of these materials were evaluated. Thermal, structural, optical and electrochemical characterization of the synthesized copolymers was carried out. These thermally stable copolymers are solution processable unlike the homopolymer. The absorption spectra indicated that with the incorporation of alkyl chains in the thiophene moiety, the onset of absorption increases and hence band gap decreases (1.47eV to 1.41eV). Bulk heterojunction solar cells were fabricated with the blend of copolymer and phenyl-C61-butyric acid methyl ester (PCBM) as the active material and device parameters were extracted. The copolymer consists of alkyl thiophene exhibit higher open circuit voltage than the copolymer consisting of thiophene moiety.

Nickel-heteropolyacids supported on silica gel for ultra-deep desulfurization assisted by Ultrasound and Ultraviolet

Heteropolyacids used as active phase precursors, a kind of desulfurization catalysts which was promoted by nickel and supported on silica gel was prepared. The prepared catalysts were then characterized by XRD and N2 physisorption, and evaluated in terms of the removal of sulfur compounds (thiophene, alkyl thiophene, BT and DBT) under the condition of Ultrasound and Ultraviolet irradiation (ODSUU). The effect of the catalyst amount on the desulfurization rate for fuel, as well as that of the reaction time, the oxidant dose, the reaction temperature and the Ultrasound and Ultraviolet irradiation time, was investigated. Under the optimized conditions for ODSUU, sulfur removal rate, up to 100% for model compounds and 99.5% for fuel, was achieved. However, sulfur removal rate under the same conditions without Ultrasound and Ultraviolet irradiation was lower than 100% for model compounds and 99.5% for fuel, which represented that catalysts assisted by Ultrasound and Ultraviolet showed better performance in the highly efficient deep removal of sulfur compounds than those of the traditional ODS procedure.

Thiophene‐Containing Pechmann Dyes and Related Compounds: Synthesis, and Experimental and DFT Characterisation

Attaching 2-thienyl residues to the Pechmann dye core chromophore (5,5-exo-dilactone situated around a C-C double bond) results in a novel magenta-coloured compound (UV/Vis spectroscopy λ(max) =570 nm in CHCl(3)), which can be rearranged to a yellow 6,6-endo-dilactone (λ(max) =462 nm in CHCl(3)). Single and double amidation results in pronounced redshift in the 5,5-exo series (violet, λ(max) =570 nm and blue, λ(max) =606 nm in CHCl(3), respectively) but pronounced blueshift in the 6,6-endo series (yellow, λ(max) =424 nm and pale yellow bordering on colourless, λ(max) =395 nm in CHCl(3), respectively). Incorporation of a 3-alkyl substituent on the thiophene ring allows for sharp increase of solubility in organic solvents concomitant with fine-tuning of the colour: a redshift in 5,5-exo-dilactones but a blueshift in 5,5-exo-dilactams. DFT computations demonstrate that both lactone classes are planar regardless of the presence of a 3-alkyl group. The lactam derivatives are non-planar: the thiophene-core chromophore dihedral angles increase on going from 5,5-exo to 6,6-endo and from thiophene to 3-alkyl thiophene. Depending on the core heteroatom (O vs. N-alkyl), ring junction (5,5-exo vs. 6,6-endo) and 3-thiophene substituent (H vs. alkyl), two, three, four or six conformers are possible. All of these conformers were characterised by DFT and were found to be very close in energy at both IEFPCM/B3LYP/DGDZVP and SMD/M06/DGDZVP levels of theory. Within each conformer set, the HOMO and LUMO energies were within 0.05 eV and the predicted λ(max) values (TD-DFT) within 10 nm, and this implies low sensitivity of the optical and electronic properties to conformation. Cyclic voltammetry measurements of selected compounds demonstrated good matching to the HOMO and LUMO energies from IEFPCM/B3LYP/DGDZVP computations. M06-2X was the best DFT functional for TD-DFT, giving predicted λ(max) values within about 20 nm.

Synthesis and properties of novel donor–acceptor copolymers based on thiophene and squaraine moieties

Two novel donor–acceptor copolymers were synthesized by Sonogashira cross-coupling of alkyl/alkoxy thiophene and dibromo-substituted squaraine moieties. The structures and properties of these polymers were characterized using FT–IR, NMR, UV–Vis, gel permeation chromatography, and cyclic voltammetry. Both copolymers are readily soluble in common organic solvents. The polymer films exhibit broad absorption in the wavelength range from 300 to 1000 nm with the maximum peaks over 750 nm. Electrochemical studies reveal that the band gaps of the polymers range from 1.05 to 1.36 eV. Compared to the alkyl thiophene, the alkoxy thiophene units can effectively lower the band gap and result in significant red-shift absorption spectrum of the resulted polymer. The strong overlap of the solar spectrum and the extremely low band gaps of the polymers suggest that they may be promising candidates for solar cells.

Magneto-optic Properties of Regioregular Polyalkylthiophenes

This paper reviews work on the magneto-optical properties of π-conjugated polymers, in particular regioregular poly(3-alkyl)thiophenes. We give an overview of the theoretical formalism that led to the first observation of Faraday rotation from thin films of poly(3-dodecyl)thiophene and experimental results, which include Faraday rotation studies from thin films composed of various polythiophene derivatives with varying degree of regioregularity We also discuss possible correlations of Faraday rotation and the supramolecular organization within the thin films of these polymers. When appropriate, we point out possible applications or suggest directions for further research. Organic magneto-optic polymer materials could reduce production costs for various magneto-optic devices, as these materials are solution processable and amenable to roll-to-roll processing.

Polymers in Biomedicine and Electronics

The versatility of polymeric materials originates from the broad variety in their chemical structure and in their hierarchical organization as well as from the possibility to realize a wide spectrum of functions. Often such functions result from a combination ofamoleculararchitecture/morphology with a physical process and therefore require integration in a suitable system (e.g. medical device, electric circuit) or environment (e.g. physiological environment). Frequently, research in the area of functional polymers is motivated by applications. This special issue focuses on two application areas, in which polymer research as well as product development are progressing rapidly: Biomedicine and Electronics. Here (multi)functional polymers are an enabling technology and in this way create substantial and sustainable value. The significance of this topic is also highlighted at the conference ‘‘Polymers in Biomedicine and Electronics’’, which takes place from Oct 3 to 5, 2010 in Berlin combining the biannual meetings of the Gesellschaft Deutscher Chemiker (GDCh) Division ‘‘Macromolecular Chemistry’’ and of the Berlin-Brandenburgischer Verband fur Polymerforschung (BVP). Topics of the conference cover the design and the synthesis of functional polymers, physical principles underlying the function, the characterization of such functionswithin a system as well as product-oriented industrial research. Smart biomaterials, biocompatible coatings and their applications in controlled drug delivery systems or in regenerative therapies will be discussed in the biomedicine-oriented sessions of the conference. Photovoltaic, charge transport, light emission aswell as sensors andactuatorswill be subjects in the area of electronics.

Low bandgap polymers synthesized by FeCl 3 oxidative polymerization

Four low bandgap polymers, combining an alkyl thiophene donor with benzo[c][1,2,5]thiadiazole, 2,3-diphenylquinoxaline, 2,3-diphenylthieno[3,4-b]pyrazine and 6,7-diphenyl-[1,2,5]thiadiazolo[3,4-g]quinoxaline acceptors in a donor–acceptor–donor architecture, were synthesized via FeCl 3 oxidative polymerization. The molecular weights of the polymers were improved by introducing o-dichlorobenzene (ODCB) as the reaction solvent instead of the commonly used solvent, chloroform. The photophysical, electrochemical and photovoltaic properties of the resulting polymers were investigated and compared. The optical bandgaps of the polymers vary between 1.0 and 1.9 eV, which is promising for solar cells. The devices spin-coated from an ODCB solution of P1DB:[70]PCBM showed a power conversion efficiency of 1.08% with an open-circuit voltage of 0.91 V and a short-circuit current density of 3.36 mA cm −2 under irradiation from an AM1.5G solar simulator (100 mW cm −2).

Tetrathiophenes with thiophene side chains: effect of substitution on packing and conjugation

Abstract The effect of substitution pattern on conjugation and packing has been investigated by synthesizing a series of tetrathiophenes with systematically varied alkyl thiophene substituents.

Long-term behavior and side chain crystallization of poly(3-alkyl thiophenes)

The influence of slow side chain crystallization and densification processes during physical aging below Tg on relaxation behavior, calorimetric properties and structure is studied for a series of regio-random poly(3-alkyl thiophenes) (P3ATs) containing C = 6–12 alkyl carbons per side chain. Shear measurements on these samples show typical features known from other nanophase-separated side chain polymers containing long alkyl groups. In particular, there is strong evidence for the existence of self-assembled alkyl nanodomains in non-crystalline samples with an independent dynamics at low temperatures indicated by an additional αPE process. Results for regio-random poly(3-dodecyl thiophene) show that the intensity of this process decreases on logarithmic time scales if methylene units crystallize within the alkyl nanodomains. This decrease is accompanied by an increase in the plateau modulus and a slowing down of the conventional α relaxation at higher temperatures. Similar but less pronounced changes are observed for poly(3-octyl thiophene) during physical aging slightly below Tg. This can be understood as precursor of side chain crystallization. The results show that densification processes driven by the crystallization tendency of the alkyl groups lead to significant changes in the properties. Interestingly, there are three different polymorphic states in which the methylene units can crystallize in poly(3-dodecyl thiophene) depending on the crystallization conditions. The influence of polymorphism on average interlayer distance dnps and overall structure is shown. A hypothetical picture describing the observed changes is proposed. The implications of the presented results for existing structural models for regio-regular P3ATs and the optimization of application relevant P3ATs containing thiophene rings and attached alkyl groups are discussed.

Evidence of Ni(0) Complex Diffusion during Grignard Metathesis Polymerization of 2,5-Dibromo-3-hexylthiophene

It has been previously reported that the Grignard Metathesis polymerization of 3-alkyl thiophenes proceeds by a quasi-“living” chain growth or “catalyst transfer polycondensation” mechanism. Several publications present data in support of the transition metal species acting as an initiator and specifically maintaining Ni(0) association with a single growing polymer chain. However, our study of 2,5-dibromo-3-hexylthiophene polymerization via GPC, MALDI-TOF, and GC-MS verifies independently and in conjunction with one another that the transition metal is involved in transfer/diffusion from chain to chain during polymerization and presents the possibility of additional mechanistic controlling factors. Kinetic monitoring and characterization studies support transfer of the transition metal through diffusion from chain to chain during polymerization.

Synthesis and characterization of a novel polymer based on anthracene moiety for organic thin film transistor

AbstractWe have designed and synthesized a new polymer, which could be used in the organic thin film transistor (OTFT). Poly[2,6‐bis(3′‐dodecythiophene‐2′‐yl)anthracene] (PDTAn), which is composed with anthracene moiety and dodecyl alkyl thiophene, was synthesized by oxidative polymerization using iron (III) chloride. The mole ratio of FeCl3 and monomer (4.2:1), keeping low temperature during the initiation reaction, amount of solvent, and dropping order were very important for oxidative polymerization without crosslinking. The molecular weight of the polymer (Mw) was measured to be 40,000 with 2.85 of polydispersity index by GPC. The physical and optical properties of the polymer were characterized by differential scanning calorimetry (DSC), cyclic voltammetry (CV), and optical absorption and photoluminescence (PL) spectroscopy. A field‐effect mobility of 1.1 × 10−4 cm2 V−1 S−1, a current on/off ratio of 105, and the Vth at −15.2 V had been obtained for OTFTs using this polymer semiconductor by solution coating. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5115–5122, 2008

Preparation and Properties of Poly(3-alkyl thiophene) and Multiwalled Carbon Nanotube Nanocomposites

not Available.

Optical Properties of Poly(3-hexylthiophene)/ZnS Nanocomposites

Nanocomposites comprised of poly(3-alkyl thiophenes)(P3ATs)/semiconductor nanoparticles exhibited excellent photoelectricity performance due to contributions from both the P3ATs and the semiconductor nanoparticles. In this study, poly(3-hexylthiophene) (P3HT) was synthesized and P3HT/ZnS nanocomposites were prepared using an in-situ method. The ZnS nanoparticles exhibited strong quantum effect on the photoluminescence (PL) properties of P3HT/ZnS and the nanocomposites exhibit an enhanced PL and red-shifted emission with increasing ZnS content. The PL quenched at ZnS-to-3HT ratio of 9.92 1 10-2 mol mol-1. The charge-transfer process between P3HT and ZnS particles is discussed. The P3HT/ZnS composites also exhibited excellent nonlinear optical (NLO) properties. The third-order NLO coefficient of P3HT/ZnS ( χ(3 ) = —6.76 1 10-12 esu) is higher than that of P3HT. The P3HT/ZnS nanocomposites have potential optical applications.

Ionic Liquid Catalyst Used in Deep Desulfuration of the Coking Benzene for Producing Sulfurless Benzene

AbstractFor the widening need of benzene used in organic synthesis, ionic liquid catalyst was prepared to study the process of deep desulfuration in the coking benzene. The result shows that the effect of de‐thiophene by the ionic liquid catalyst (N‐methyl imidazolium hydrogen sulfate [Hmim][HSO4]) is related to its acid function value. Hammett indicator was used to determine the acid function value H0 of the ionic liquid. It can be concluded that while the acid function value is in the range from −4 to −12, the ionic liquid catalyst can make the concentration of thiophene in the coking benzene be under 0.5 mg·L−1. Similarly to the catalytic mechanism of solid acid, with a certain acid quantity and strength, the ionic liquid catalyst helps to form alkyl thiophene through Friedel‐Crafts reaction, which differs from the character of benzene and it is absolutely necessary for the separation and refinement of benzene. But overabundant quantity and higher acid value of [Hmim][HSO4] are more suitable for the side copolymerization of benzene, thiophene and alkene, thereby affecting repeated use of the ionic liquid catalyst([Hmim][HSO4]). In our research, thiophene derivant produced by desulfurization in the coking benzene was used as the polymer to provide the passing channel of the charges. The ionic liquid composition in poor performance after repeated use was made to prepare conductive material (resisting to static electricity) as an "electron‐receiving" and "electron‐giving" doping agent. The result shows that thiophene derivant after desulfuration in the coking benzene can be used to prepare doping conductive materials.

Corrosion protection of carbon steel by thin films of poly(3-alkyl thiophenes) in 0.5 M H 2SO 4

Poly(3-octyl thiophene) (P3OT) and poly(3-hexylthiophene) (P3HT) dissolved in toluene were deposited onto 1018 carbon steel and corroded in 0.5 M H 2SO 4. P3OT and P3HT films were chemically deposited by drop casting onto 1018-type carbon steel with two surface finishing, i.e. abraded with 600-emery paper and with alumina (Al 2O 3) particles of 1.0 μm in diameter (mirror finish). Their corrosion resistance was estimated by using potentiodynamic polarization curves, linear polarization resistance (LPR), and electrochemical impedance spectroscopy, EIS, techniques. In all cases, polymeric films protected the substrate against corrosion, but the protection was improved if the surface was polished with Al 2O 3 particles of 1.0 μm in diameter. The polymer which gave the best protection was P3HT because the amount of defects was much lower than that for the P3OT films. The polymers did not act only as a barrier layer against aggressive environment, but they improved the passive film properties by decreasing the critical current necessary to passivate the substrate, increasing the pitting potential and broadening the passive interval.