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A new side-chain C60-fullerene functionalized thiophene copolymer bearing tributylphosphine-substituted hexylic lateral groups was successfully synthesized by means of a fast and effective post-polymerization reaction on a regioregular ω-alkylbrominated polymeric precursor. The growth of the polymeric intermediate was followed by NMR spectrometry in order to determine the most convenient reaction time. The obtained copolymer was soluble in water and polar solvents and was used as a photoactive layer in single-material organic photovoltaic (OPV) solar cells. The copolymer photovoltaic efficiency was compared with that of an OPV cell containing a water-soluble polythiophenic homopolymer, functionalized with the same tributylphosphine-substituted hexylic side chains, in a blend with a water-soluble C60-fullerene derivative. The use of a water-soluble double-cable copolymer made it possible to enhance the control on the nanomorphology of the active blend, thus reducing phase-segregation phenomena, as well as the macroscale separation between the electron acceptor and donor components. Indeed, the power conversion efficiency of OPV cells based on a single material was higher than that obtained with the classical architecture, involving the presence of two distinct ED and EA materials (PCE: 3.11% vs. 2.29%, respectively). Moreover, the synthetic procedure adopted to obtain single material-based cells is more straightforward and easier than that used for the preparation of the homopolymer-based BHJ solar cell, thus making it possible to completely avoid the long synthetic pathway which is required to prepare water-soluble fullerene derivatives.

Side-chain C60-fullerene functionalized alkylthiophene copolymers with different regioregularity and fullerene content are successfully synthesized using a simple and straightforward post-polymerization functionalization procedure based on a Grignard coupling reaction. The products are employed as single materials in photoactive layers of organic photovoltaic solar cells. The use of double-cable polymers allows an enhanced control on the nanomorphology of the active blend, reducing the phase-segregation phenomena as well as the macroscale separation between the electron acceptor and donor components. With the insertion of a thin layer of gold nanoparticles between buffer and active layer of the cells, a conversion efficiency of 5.68% is obtained. Moreover, an increased stability over time is achieved when the copolymers are photocrosslinked immediately after the annealing procedure, leading to acceptable efficiencies even after 80 h of accelerated ageing, a key feature for widespread applicability of the prepared devices.

In this paper we present the synthesis and characterization of two novel copolymers obtained from a bithiophene unit carrying octylsulfanyl side chains and thienothiophene units substituted with keto (PK) or ester (PE) groups. Their structural, electrochemical and photophysical properties were investigated by gel permeation chromatography (GPC), thermogravimetric analysis (TGA), NMR, UV-visible-NIR spectroscopy, cyclic voltammetry (CV) and atomic force microscopy (AFM). They possess good solubility in common organic solvents, filmability, proneness to form π-stacks, moderate solvatochromism, good thermal stability and low band gap energy. They were tested as donor materials in combination with [70]PCBM (electron acceptor) in bulk-heterojunction polymer solar cells. The geometry of the devices is: glass/ITO/PEDOT:PSS/copolymer:[70]PCBM/Ca/Al. The external quantum efficiency curve of the best device, realized using a blend of PK : [70]PCBM, 1 : 2 weight ratio, shows a broad response from 350 to 1000 nm. The power conversion efficiency under 100 mW cm-2 AM 1.5G illumination is greater than 1%. © 2014 The Royal Society of Chemistry.

The solvatochromic behavior of chloroform solutions of poly(3-decyl-2,5-thienylene), poly[3-(10-hydroxydecyl)-2,5-thienylene] and their copolymers was studied by the addition of the non-solvent methanol. A reversed chromic transformation was found associated with the content of the hydroxyalkyl substituent. This anomalous effect was investigated using a number of non-solvents, in particular aliphatic alcohols from methanol up to decanol. In the case of a chloroform/methanol mixture, which gives the maximum anomalous effect, the effect produced by temperature variation was also examined. An explanation based on a molecular approach was attempted.

The chromic behaviour of a soluble ω-hydroxydecyl 3-substituted polythiophene has been investigated by UV-VIS spectroscopy in different solvent/non-solvent mixtures over a wide range of low temperatures. Some interesting new effects have been observed that is the first case of a reversal of the solvatochromic transformation in substituted polythiopenes and a concentration effect in dilute pure solvent solutions. A molecular approach based on solvent-polymer interactions has been adopted to study the conformational chromic transformation of the polymer. © 2001 Elsevier Science B.V.

The poly(3-hexanoyloxyethyl-2,5-thienylene) was studied by means of mono-and bidimensional nuclear magnetic resonance spectroscopy. The regiochemistry of the polymer is assigned on the basis of the 13C chemical shifts, which are easily obtained through inverse detection experiments, utilizing a triad-based model. © 1997 Elsevier Science Ltd. All rights reserved.

We describe the synthesis of alternating bithiophene–fluorene copolymers (P1–P3) with different regiochemistry of the bithienyl unit and different alkylsulfanyl chain lengths. The structural, electrochemical and photophysical properties of these polymers were investigated by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), NMR, UV/Vis and photoluminescence (PL) spectroscopy and cyclic voltammetry (CV), and the polymers were used to assemble organic solar cells (OSCs), in combi-nation with the fullerene derivative methyl [6,6]-phenyl-C61- butyrate (PCBM). P3, with a head-to-head bithienyl unit, shows a broader absorption and a lower band gap with respect to P1 and P2, which have tail-to-tail bithienyl units. The PL intensity of P1–P3 is dramatically quenched in the presence of PCBM, demonstrating that an efficient charge transfer between donor and acceptor occurs. The best OSC device was obtained with P3

Full Paper: Functionalized second-order nonlinear optical (NLO) thiopene copolymers were synthesized. Two elegant syntheses based on the post-functionalization of polymeric precursors obtained by oxidative polymerization were developed, leading to copolymers that proved to be fully soluble in common organic solvents. The new materials were characterized by NMR, FT-IR, and UV-vis spectroscopies, gel permeation chromotography (GPC), and thermogravimetric analysis (TGA). Moreover, the NLO activity of the new materials, as determined by corona poling alignment and second harmonic generation (SHG) measurements, showed a good agreement between the second-order NLO coefficient and the chromophore concentration.

For the purpose of preparing materials for nonlinear optics applications, a 3-ethylthiophene bearing an NLO-active chromophoric group as a substituent at the end of the ethylic chain was copolymerized with 3-hexylthiophene. Different FeCl3-based oxidative polymerization conditions in solvents such as CH3NO2 and CCl4 and their effects on the copolymers characteristics and solubility in CHCl3 (i.e., the copolymer's soluble fraction) were examined. This work allowed to achieve a satisfactory chloroform-soluble fraction of the copolymer, still containing a notable amount of NLO-active group, and to tune to some extent the main characteristics of the copolymer; moreover, the behavior of the monomers−solvent−oxidant system was investigated.

The synthesis of poly(3, 3″- and 3′, 4′-dialkyl-2, 2′:5′, 2″-terthiophene)s possessing a full ordered regiochemistry of bonding and substitution, as well as a conjugated chain with the minimum possible amount of steric interactions between the substituents, is described. The synthesis was achieved through the simplest chemical method, namely the oxidative polymerization reaction based on FeCl 3 as oxidant. The structural regularities of the polymers have been confirmed by Fourier transform infra-red ( FT i.r.) and 1 H nuclear magnetic resonance (n.m.r.) spectroscopy. Experimental conditions of special interest for improving the yields and molecular weights of the neutral soluble polymers are discussed.

Novel optically active oligothiophenes bearing electron-donating chiral side chains have been prepared by synthetic methods suitable to achieve regioregular head-to-tail and head-to-head/tail-to-tail derivatives. In particular, the chiral (S)-(2-methyl)butyl moiety was linked at position 3 of the thiophene ring through heteroatoms, such as S or O, to evaluate its effect on the macro molecular aggregation and, consequently, on the chiroptical properties of the material in the solid state. The materials have been fully characterized and investigated by optical and chiroptical methods upon aggregation both from the solution and as cast films. Compared with the related head-to-tail and head-to-head/tail-to-tail poly(3-alkyl)thiophene derivatives, with the same optically active moiety directly linked to the ring and possessing a higher polymerization degree, the chiroptical properties of the newly synthesized oligomers were significant, or even better, and provided insight into the role of intrachain-interchain interactions between the heteroatom and the thienyl sulfur atom.