Soluble Polythiophene Research Articles

Effects of Water/Alcohol Soluble Cationic Polythiophenes as Cathode Interlayers for Eco‐Friendly Solar Cells

AbstractThree new ionic polythiophene derivatives, soluble in polar solvents, are synthesized with good yields using simple, low‐cost, and straightforward procedures. They are investigated as interfacial cationic conjugated polyelectrolyte (CPE) layers for halogen‐free bulk heterojunction polymeric solar cells, based on a water‐soluble electron‐donor polymer (poly[3‐(6‐diethanolaminohexyl)thiophene]) and a water‐soluble electron‐acceptor fullerene derivative (malonodiserinolamide fullerene). The simple insertion of the CPE interlayer between the active layer and the aluminum cathode dramatically increases the power conversion efficiency of the final device up to nearly 5%, resulting from a decrease of the electrode work function, improved electron extraction, and optimization of the morphology of the layers. The obtained results demonstrate that the incorporation of CPE layer is a powerful and convenient methodology for the development of highly efficient and eco‐friendly processable polymeric solar cells.

Synthesis of a soluble adenine-functionalized polythiophene through direct arylation polymerization and its fluorescence responsive behavior

An adenine-functionalized polythiophene is synthesized via direct arylation polymerization using Boc-protection to overcome catalyst deactivation. The resulting copolymer is highly soluble and shows reversible fluorescence quenching.

Photoactive Boron-Nitrogen-Carbon Hybrids: From Azo-borazines to Polymeric Materials.

In this paper, we describe synthetic routes for preparing a novel switchable BNC-based chromophore, composed of a borazine core peripherally functionalized with azobenzene moieties. Capitalizing on the Pd-catalyzed Suzuki cross-coupling reaction between a tris-triflate borazine and an organoboron azobenzene derivative, a photoswtichable azo-borazine derivative was successfully prepared. The molecule showed reversible E/Z photoisomerization upon irradiation at the maximum of the intense π-π* absorption feature (360 nm). X-ray crystallographic investigations revealed a nonplanar orientation of the three azobenzene moieties and the trans configuration of the -N═N- bonds. Building on the synthetic versatility of the borazine-azobenzene derivative, we used this photoactive scaffold to engineer soluble BN-doped polythiophene polymers. Photophysical characterization performed in solvents of different polarity suggested that the polymer undergoes intramolecular charge transfer (ICT).

Synthesis, Characterization and Cell Imaging of Water Soluble Polythiophene Derivative†

Synthesis, Characterization and Cell Imaging of Water Soluble Polythiophene Derivative†

Charge Transport in Conjugated Polymers with Pendent Stable Radical Groups

Synthesizing a stable radical polymer with a conjugated backbone seems like a natural way to introduce conductivity to radical polymers, which are traditionally synthesized with insulating, nonconjugated backbones. For charge storage applications that take advantage of the redox-active nature of stable radical polymers, enhanced conductivity would improve performance. To explore the interplay between stable radicals and a conjugated backbone, we prepared and studied soluble polythiophene with high regioregularity and various concentrations of pendent radical groups to systematically examine any change in conductivity with radical incorporation. Using electron paramagnetic resonance and electrical conductivity measurements, we show that there is an exponential decrease in conductivity as we increase the percentage of pendent groups attached to repeating units, which changes the conductivity by 6 orders of magnitude between the nonradical control polythiophene material and the material with the highest radi...

Aqueous Processing for Printed Organic Electronics: Conjugated Polymers with Multistage Cleavable Side Chains.

The ability to process conjugated polymers via aqueous solution is highly advantageous for reducing the costs and environmental hazards of large scale roll-to-roll processing of organic electronics. However, maintaining competitive electronic properties while achieving aqueous solubility is difficult for several reasons: (1) Materials with polar functional groups that provide aqueous solubility can be difficult to purify and characterize, (2) many traditional coupling and polymerization reactions cannot be performed in aqueous solution, and (3) ionic groups, though useful for obtaining aqueous solubility, can lead to a loss of solid-state order, as well as a screening of any applied bias. As an alternative, we report a multistage cleavable side chain method that combines desirable aqueous processing attributes without sacrificing semiconducting capabilities. Through the attachment of cleavable side chains, conjugated polymers have for the first time been synthesized, characterized, and purified in organic solvents, converted to a water-soluble form for aqueous processing, and brought through a final treatment to cleave the polymer side chains and leave behind the desired electronic material as a solvent-resistant film. Specifically, we demonstrate an organic soluble polythiophene that is converted to an aqueous soluble polyelectrolyte via hydrolysis. After blade coating from an aqueous solution, UV irradiation is used to cleave the polymer’s side chains, resulting in a solvent-resistant, electroactive polymer thin film. In application, this process results in aqueous printed materials with utility for solid-state charge transport in organic field effect transistors (OFETs), along with red to colorless electrochromism in ionic media for color changing displays, demonstrating its potential as a universal method for aqueous printing in organic electronics.

Effect of side groups on two-photon absorption of soluble polythiophenes

ABSTRACTThe effect of pendant side groups on two-photon absorption cross-section in a number of soluble fluorescent polythiophenes was investigated. Different side groups lead to different planarity and conformation of the polymer. As the side-group-induced planarity of the polymer chain increases, the two-photon absorption cross-section also increases. The increased delocalization of the π-electrons along the polymer backbone enhances the third-order optical nonlinearity. The aggregation of the polymer chain in solution lowers the quantum efficiency of fluorescence and decreases the two-photon absorption cross-section. This study demonstrates a novel method of enhancing the two-photon absorption cross-section by tuning the pendant side group.

Flexible and conductive multilayer films based on the assembly of PEDOT:PSS and water soluble polythiophenes

Flexible conductive polyelectrolyte multilayer films built upon anionic poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and cationic poly(3-hexylthiophene)-based conjugated polyelectrolytes (P3HT-R) containing imidazolium, pyridinium and phosphonium ionic groups were prepared using electrostatic layer-by-layer assembly. Adsorbed amount of each polyelectrolyte strongly increases when divalent cations (Ba2+) are employed as electrolyte and when the rinsing step is avoided during the build-up. The electrical properties of these (P3HT-R/PEDOT:PSS)n multilayer films were then investigated using the van der Pauw method leading to an average conductivity of ∼2 S m−1. Semiconducting behavior of these organic coatings was demonstrated by the direct relationship between the conductivity and the temperature. (P3HT-R/PEDOT:PSS)n multilayer films exhibited p-type semiconducting behavior as showed by Seebeck measurements. Finally, these films were successfully deposited onto flexible polymer sheets and their conductivity was found to be not affected by applying a bending stress.

Pentafluorobenzene end-group as a versatile handle for para fluoro "click" functionalization of polythiophenes.

A convenient method of introducing pentafluorobenzene (PFB) as a single end-group in polythiophene derivatives is reported via in situ quenching of the polymerization. We demonstrate that the PFB-group is a particularly useful end-group due to its ability to undergo fast nucleophilic aromatic substitutions. Using this molecular handle, we are able to quantitatively tether a variety of common nucleophiles to the polythiophene backbone. The mild conditions required for the reaction allows sensitive functional moieties, such as biotin or a cross-linkable trimethoxysilane, to be introduced as end-groups. The high yield enabled the formation of a diblock rod-coil polymer from equimolar reactants under transition metal-free conditions at room temperature. We further demonstrate that water soluble polythiophenes end-capped with PFB can be prepared via the hydrolysis of an ester precursor, and that such polymers are amenable to functionalization under aqueous conditions.

Ion Selection by Redox Changes in a Soluble Helical Polythiophene Channel

Molecular dynamics are applied to simulate molecular motions in an aqueous solution of two soluble derivatives of a 100-ring polythiophene chain – one with sidechains terminating in a SO3– group, the other in NMe3+. Each chain is in a helical conformation defining a water-containing central channel along whose axis the dynamics of ions from the solution to the channel’s axial electrostatic potential is simulated. The profiles of these potentials distinguish the tendencies of the two channel species to occlude water molecules on their surfaces. Invoking the conductive polymer characteristics of polythiophene that can accomplish the transfer of electrons between the aromatic rings and redox reagents in the solution, the effect of this transfer on the axial potential and migration is followed. The electrostatic potential monitors differences in the association of the solvent molecules with the two species of helical polymer and shows that while Na+ and Cl– ions do not enter the channel in the absence of the redox changes, an ion with a selected charge does so spontaneously when appropriate electric charge is transferred to the channel. This enables the selected ion to travel about 10 – 20Å in the channel without the application of an external electric field.

Synthesis of Soluble Ferrocene-Based Polythiophenes and Their Properties

Ferrocene-based polythiophenes are the promising class of the functional materials, but mostly the polythiophenes are insoluble in common solvents except some derivatives of polythiophenes like poly(3-hexylthiophene) (P3HT). Herein, two new ferrocene-based thiophene monomers, 2-(thiophen-3-yl) ethyl ferrocenoate and 2-(thiophen-3-yl) methyl ferrocenoate were synthesized and copolymerized with 3-hexylthiophene (3HT) respectively. The resulting polymers were soluble (in common organic solvents) and processable. The synthesis and the molecular weights were confirmed by the 1H-NMR and GPC studies respectively. Poly (TEF-co-3HT) was subjected to study the electrochemical properties in comparison of respective monomers and ferrocene. It was found that the resulting copolymer had the combined redox properties of its monomers. Also, very interestingly, the copolymer showed improved reversible redox properties which were not only better than its parent monomers but even better than the pure ferrocene. Photoemission spectra of P3HT and Poly (TEF-co-3HT) were also rerecorded and compared with each other.

ChemInform Abstract: Water Soluble Polythiophenes: Preparation and Applications

AbstractReview: 129 refs.

Water soluble polythiophenes: preparation and applications

Different synthetic procedures for water soluble polythiophenes and their applications in sensing, detection of biomolecules and optoelectronic devices are discussed.

Novel regioregular polythiophenes containing side-chain porphyrin groups for polymeric photovoltaic cells

The paper presents a new strategy for the preparation of porphyrin-functionalized head-to-tail regioregular thiophene copolymers using a simple and effective post polymerization functionalization (PPF) procedure based on the synthesis of a regioregular and soluble polythiophene precursor followed by subsequent reaction with a suitably functionalized porphyrin derivative. Thus, thiophene copolymers poly[3-(6-bromohexyl)thiophene-co-(3-[5-(4-phenoxy)-10,15,20-triphenylporphyrinyl] hexylthiophene)]s at different porphyrin chromophore contents were prepared, obtaining, in all cases, very soluble and easily filmable derivatives. Their thermal, optical and electrochemical properties were determined and their performances as the active layer in bulk heterojunction solar cells tested.

Hybrid TiO2 Solar Cells Produced from Aerosolized Nanoparticles of Water-Soluble Polythiophene Electron Donor Layer

Hybrid solar cells (HSCs) with water soluble polythiophene sodium poly[2-(3-thienyl)-ethyloxy-4-butylsulfonate] (PTEBS) thin films produced using electrospray deposition (ESD) were fabricated, tested, and modeled and compared to devices produced using conventional spin coating. A single device structure of FTO/TiO2/PTEBS/Au was used to study the effects of ESD of the PTEBS layer on device performance. ESD was found to increase the short circuit current density (Jsc) by a factor of 2 while decreasing the open circuit voltage (Voc) by half compared to spin coated PTEBS films. Comparable efficiencies of 0.009% were achieved from both device construction types. Current-voltage curves were modeled using the characteristic solar cell equation and showed a similar increase in generated photocurrent with an increase by two orders of magnitude in the saturation current in devices from ESD films. Increases in Jsc are attributed to an increase in the interfacial contact area between the TiO2 and PTEBS layers, while decreases in Voc are attributed to incomplete film formation from ESD.

Smectic-phase-induced interdigitated orientation of polythiophenes bearing phenylnaphthalene mesogen

Polythiophenes bearing mesogenic phenylnaphthalene side chains at 3-position, poly(3-{10-[6-(4-octylphenyl)naphthalene-2-yloxy]decyl}thiophene-2,5-diyl) and poly(3-{10-[4-(6-octyl-2-naphthyl)phenyloxy]decyl}thiophene-2,5-diyl), in which each mesogenic core linked reversely, and their model liquid crystals corresponding to each phenylnaphthalene side chains were synthesised and compared each other to investigate liquid crystalline property and molecular arrangement. Yamamoto polymerisation of corresponding 2,5-dibromothiophene monomers afforded soluble polythiophenes. They had similar number average molecular weights about 10 kDa and exhibited similar photophysical properties, i.e, UV–vis absorption λmax due to polythiophene backbones around 390 nm and fluorescence λmax around 540 nm in solution (560 nm in film state) with energy transfer from an excited phenylnaphthalene side group to the backbone. The respective model liquid crystals showed different behaviours of phase transition temperatures, enthalpies, and reversibility, whilst both polymers had similar phase transition behaviours. A well-developed fan-shaped texture in the temperature range between isotropic liquid and glass phases was observed for the polymers by polarising optical microscopy. It is suggested that both polymers had an almost identical smectic A1 phase, which led to glass state by retaining the interdigitated molecular arrangement through a crystal E phase on cooling.

Cationic polythiophenes as responsive DNA-binding polymers

A new water soluble cationic polythiophene derivative, poly(N,N,N-trimethyl-3-(2-(thiophen-3-yl)acetamido)propan-1-aminium iodide), was synthesized via two consecutive post-polymerization functionalizations of poly(methyl 2-(thiophen-3-yl)acetate). This conjugated polymer binds DNA at N/P = 5 and forms polyplexes at N/P = 10. Its potential use as a theranostic gene delivery vehicle is investigated here.

Synthesis of Soluble Polythiophene Partially Containing 3,4-Ethylenedioxythiophene and 3-Hexylthiophene by Polycondensation

A novel poly(quinquethiophene) partially containing 3,4-ethylenedioxythiophene (EDOT) and 3-hexylthiophene, poly(3,3 ''''-dihexyl-3',4',3''',4'''-diethylenedioxy-2,2':5',2'':5'',2''':5''',2''''-quinquethiophene), was synthesized by three types of polycondensations. Among them, direct C-H coupling reaction gave the polymer with the highest molecular weight. The resulting polymer was soluble in common organic solvents. Absorption and fluorescence spectra of the polymer showed a remarkable red-shift compared with the corresponding monomer due to the expansion of effective π-conjugation length.

Soluble polythiophenes as anticorrosive additives for marine epoxy paints

This study compares the resistance against corrosion of a marine epoxy primer modified with Zn3(PO4)2 (10 wt%) or a small concentration (0.3 wt%) of conducting polymer (CP) as inorganic or organic anticorrosive pigment, respectively. More specifically, the behavior of three different CPs has been evaluated: polyaniline (PAni) emeraldine base, poly(3-thiophen-3-yl-acrylic acid methyl ester) and poly(2-thiophen-3-yl-malonic acid dimethyl ester), the latter two being soluble polythiophene (PTh) derivatives bearing carboxylate side groups. In a first stage, the structural, thermal, and mechanical properties of all the modified epoxy coatings were characterized using infrared spectroscopy, thermogravimetric analyses and stress–strain assays, respectively. After this, accelerated corrosion assays have evidenced that the degree of protection imparted by a small concentration of PAni is higher than that obtained using 10 wt% of Zn3(PO4)2. Indeed, PAni has been found to be more effective as anticorrosive additive than the two PTh derivatives. This fact has been attributed to the electroactivity of the former, which is higher than that of the latter. Thus, the ability to store charge has been proposed to be also responsible of protection against corrosion imparted by organic additives, based on CPs.

「光エネルギー変換人工膜」としての次世代有機系太陽電池

Next-generation solar cells based on new concepts and/or novel materials are currently attracting wide interests. The solar cell is recognized as “Artificial Membrane for Photo-energy Conversion”. Among new types of solar cells, dye-sensitized solar cell (DSSC) have received much attention as the low-cost solar cell. In our study, panchromatic photoelectric conversion up to around 1000 nm has been accomplished by the use of new sensitizer. We prepared the mechanical stack tandem solar cell showing a high overall power conversion efficiency (η) of about 12%. On the other hand, polymer-sensitized solar cell (PSSC) were constructed as hybrid organic solar cell by the use of novel soluble polythiophene derivatives with hydrophilic anchoring units. The PSSC sensitized with two types of the polymers yielded higher IPCE values in the visible region because of dual-sensitization. As for the other hybrid organic photovoltaics, surface complexes formed of TiO2 with dicyanomethylene compounds (TCNX) were used for the solar cells where the charge separation occurs directly by the charge-transfer transitions. At the last part, a three-electrode solar rechargeable battery, namely “energy-storable dye-sensitized solar cell (ES-DSSC)” was described.