Search

A Raman spectroscopy and theoretical study to find an unconventional structure-property relationship. A larger planarity forms an alternative truncated conjugation pathway that hinders the beneficial a-conjugation selenophene pathway.

Memory and synaptic devices based on three IDTT-based copolymers were investigated.

The relationship between backbone fluorination and the solid-state properties of semiconducting polymers was evaluated to unveil the impact on thermomechanical properties.

Ladder-type thiazole-fused S,N-heteroacenes with an extended π-conjugation consisting of six (SN6-Tz) and nine (SN9-Tz) fused aromatic rings have been synthesized and fully characterized.

Understanding the strategy of fluorination to control π-conjugation and intra and interchain interactions for the rational design of improved semiconducting polymers.

Ladder-type thiazole-fused

The structural rigidity of fused units in the polymer backbone, in addition to the resulting stabilizing effect of the quinoidal structure, and tunable electronic properties have played a key role in promoting highly-ordered π-stacking moieties, exhibiting promising charge carrier mobilities. The electron-deficient thiazole moiety shows high planarity and effective π–π stacking, which leads to the reduction in the energy levels of the highest occupied and lowest unoccupied molecular orbitals (HOMO/LUMO), and ideally enhances the electron charge mobility. Four heterocycle-based monomers BTzS, BTzSe, DTS, and DTG based on fused bithiazole and dithiophene units incorporated with sulfur, selenium, silicon, and germanium as the bridging atoms were synthesized and characterized. The monomers were copolymerized with the electron-rich alkylated thienylenevinylene (TV) unit to afford copolymers P1–P4. The thermal, optical, and electrochemical properties and crystallinity of the copolymers were thoroughly investigated. Extensive OFET device optimization using different solvents and annealing temperatures resulted in the best charge mobility of 0.09 cm2 V−1 s−1 for the electron-deficient bithiazole BTzS copolymer P1 and 0.36 cm2 V−1 s−1 for the DTS copolymer P3.

Imide-functionalized organic monomers and polymers are attractive in organic optoelectronic devices due to the strong electron-withdrawing ability of the carbonyl units. We report the synthesis of ...

The synthesis and characterization of asymmetric alkoxy- are reported, fluoro-benzothiadiazole (BT) acceptor core derivatized with a series of six different heterocycles (selenophene, thiophene, furan, 5-thiazole, 2-thiazole and 2-oxazole). The effect of the flanked-heterocycles containing different chalcogen atoms of the six homopolymers (HPX) is studied using optical, thermal, electrochemical, and computational analysis. Computational calculations indicate a strong relationship between the most stable conformation for each homopolymer and their bearing heterocycle, thus homopolymers HPSe', HPTp', HPFu', and HPTzC5, adopted the syn-syn and syn-anti conformations due to their noncovalent interactions with shorter distances, while HPTzC2' and HPOx' demonstrate preference for the anti-anti conformation. Optical property studies of the homopolymers reveal a strong red-shift in solution and film upon exchanging the chalcogen atom from OxygenSulfurSelenium in HPFu, HPTp, and HPSe, respectively. In addition, deeper highest occupied molecular orbital (HOMO) energy levels are observed when the donor-acceptor moieties (HPSe, HPTp, and HPFu) are substituted for the acceptor-acceptor systems such as HPTzC5, HPTzC2, and HPOx. Improved packing and morphology are exhibited for the donor-acceptor homopolymers. Thus, having a flanked heterocycle containing different chalcogen-atoms in polymeric systems is one way of tuning the physicochemical properties of conjugated materials for optoelectronic applications.

The synthesis, characterisation and photovoltaic performance of an indacenodithiophene (IDT)-based organic dye in DSSCs has been presented. The dye was designed with a novel A-D-A system, which combines the advantages of a large, pi-extended donor core, flanked with double acceptor/anchoring groups. The studies presented herein illustrate the utility of the IDT core as an efficient energy-level mediator, and fluorescence resonance energy-transfer module operating via intramolecular charge transfer (ITC). in contrast to the current dyes used for DSCCs, the excitation in the IDT moiety occurs symmetrically along the long axis of the molecule, representing a new pathway of development of DSSCs. This compact system when fabricated into a metal free dye sensitized solar cell achieves promising power conversion efficiency of up to 4.2%, with a high short-circuit current density (J(sc)) of 11.69 mA cm(-2) and open-circuit voltage (V-oc) of 0.6 V and fill factor (FF) of 0.6 under AM 1.5 irradiation (100 mW cm(2))., Qatar National Research Fund (QNRF); National Priorities Research Program [NPRP 12S-0304-190227], This work was supported by the Qatar National Research Fund (QNRF) and the National Priorities Research Program, project number NPRP 12S-0304-190227. The numerical calculations reported here were performed in part at the TUBITAK ULAKBIM, High Performance and Grid Computing Centre (TRUBA resources).

The benzoxazines of three naturally occurring phenylpropanoid phenols: ferulic, coumaric, and phloretic acids, and their esters are described. Benzoxazines with conjugated unsaturated chains exhibit unusual poor thermal stability and degrade partially at the polymerization temperature making necessary the use of a catalyst (BF3.Et2O) to low the polymerization temperature and prevent degradation. Polybenzoxazines are prepared thermally and characterized by DSC and TGA techniques. The resulting materials have superior Tgs when compared with those prepared from an unsubstituted monofuctional benzoxazine due to the additional crosslinking through the ester and carboxylic moieties. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4894–4903

Filiació URV: SI An efficient route to obtain allyl- and propargyl-containing diols from 10-undecen-1-ol, and their polymerization with isophorone diisocyanate to produce alkene- and alkyne-functionalized polyurethanes (PUs) is described. The bio-based PUs have been further modified by thiol-ene/yne coupling of thioglycerol into unsaturation to obtain a series of PUs with enhanced hydrophilicity. All the synthesized PUs were characterized by FTIR-ATR and NMR spectroscopy. As expected, the PUs were amorphous and DSC revealed glass transition temperatures in the range of 40 °C¿5 °C for the PUs before and after modification. The PUs exhibited highly tunable thermal and mechanical properties. The mechanical properties of these bio-based polymers (E modulus from 774 MPa to 6 MPa and at break from 45% to 401%) make the suitable materials for a large range of applications.

Filiació URV: SI An efficient route to obtain allyl- and propargyl-containing diols from 10-undecen-1-ol, and their polymerization with isophorone diisocyanate to produce alkene- and alkyne-functionalized polyurethanes (PUs) is described. The bio-based PUs have been further modified by thiol-ene/yne coupling of thioglycerol into unsaturation to obtain a series of PUs with enhanced hydrophilicity. All the synthesized PUs were characterized by FTIR-ATR and NMR spectroscopy. As expected, the PUs were amorphous and DSC revealed glass transition temperatures in the range of 40 °C¿5 °C for the PUs before and after modification. The PUs exhibited highly tunable thermal and mechanical properties. The mechanical properties of these bio-based polymers (E modulus from 774 MPa to 6 MPa and at break from 45% to 401%) make the suitable materials for a large range of applications.

A family of supramolecular side-chain ionic polyurethanes (PUs) is synthesized by a simple method using polyurethanes with tertiary amines as pendant groups, and carboxylic acids. The resulting polyurethanes contain diethyl ammonium and carboxylate moieties that are bonded by a combination of ionic and hydrogen bonds. The self-assembling process is observed by Fourier-transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) and nuclear magnetic resonance (NMR) spectroscopy. The synthesized polyurethanes are characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Rheological, dielectric, and mechanical properties are investigated, and it is found that the tunability of the properties depends on the acid functionality and the chain length. Dynamic viscoelastic tests reveal a rapid and complete thermal reversibility, which opens the door to studying the recyclability of the samples.