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A hitherto unreported heterocyclic imide, thiadiazolo[3,4-g]quinoxaline-fused acenaphthenequinone imide acceptor (TQAI), is designed and synthesized by incorporating an auxiliary electron-deficient...

Donor–acceptor (D–A) conjugated polymers with the band gaps below 1.0 eV can exhibit unique near-infrared (NIR) activities and multiple functional applications. However, it is still a big challenge...

Lactam-containing conjugated molecules are important building blocks for conjugated polymers for high performance organic field-effect transistors (OFETs). The alkylation on conjugated lactam building blocks may preferably produce either O-alkylated or N-alkylated isomers, which might have different influences on the HOMO/LUMO energy levels, π–π stacking patterns and crystallinity of the corresponding polymers. However, the influence of O-alkylation and N-alkylation on the OFET performance of the resultant polymers has not been reported. Here, with an improved synthetic strategy, we prepared the N-alkylated isomer of dibenzonaphthyridinedione (DBND), a tetracyclic lactam building block that used to give O-alkylated product preferably, which gave us a chance to compare the influence of N-alkylated DBND (N-DBND) and O-alkylated DBND (O-DBND) on the OFET performance of the corresponding polymers. It was found that the polymer based on N-DBND exhibits a much higher hole mobility (0.55 cm2 V–1 s–1), almost 100...

A new solution-processable conjugated copolymer (P1) of perylene diimide (PDI) and dithienothiophene (DTT) incorporating acetylene spacers was synthesized by palladium(0)-catalyzed Sonogashira coupling reaction. Theory calculation reveals that introduction of rod-like ethynylene spacer in the polymer main chain promotes planarity and π-conjugation of the polymer main chain. Relative to the conjugated copolymer (P2) of PDI and DTT without acetylene spacers, polymer P1 exhibits 0.1 eV down shift of LUMO level and 89 nm red shift of low-energy absorption band. Polymer P1 in top-contact bottom-gate organic field-effect transistors (OFETs) exhibits a saturation electron mobility of 0.06 cm2 V–1 s–1 in air, while P2 does not function in the same device in air. Additionally, a saturation electron mobility of 0.075 cm2 V–1 s–1 in air, and after six days storage in air, an electron mobility of 0.034 cm2 V–1 s–1 were observed for P1 in bottom-contact bottom-gate OFETs; while a saturation electron mobility of 0.038 ...

Two new dendronized nonlinear optical (NLO) polyfluorenes were synthesized with high azo-chromophore loading density by the introduction of high generation chromophore dendrons on the side chains. Thanks to the advantages of Sharpless’ click chemistry reaction, the dendrons were conveniently bonded to the backbone of polyfluorene with the conversion of 100%, although they were really very bulky. The new-formed triazole rings in the dendrons acted as suitable isolation groups to minimize the strong dipole−dipole interactions among the polar chromophore moieties to improve NLO effects, according to the results obtained from UV−vis spectra and order parameters. All the polymers were well characterized and exhibited good solubility, high thermal ability, wide optical window, and large NLO effects (up to 106.0 pm/V). In addition, the tested NLO results of these dendronzied polymers demonstrated a deviation from the dipolar frustration that typically limits the NLO effect in conventional chromophore/polymer com...

By modifying the synthetic procedure, the previous reported impossible approach was successfully utilized to construct new azo-chromophore-containing hyperbranched polymers (HP1 and HP2) from AB2 m...

Two poly ( thieno [ 3, 2- b] thiophene vinylene ) derivatives ( P2 and P3 ) were prepared by Pd -catalyzed Stille -coupling method. Compared with poly ( 3- hexylthienylene vinylene ) ( P1 ), strong photoluminescence was observed for P2 and P3 solutions, while the maximum absorption of P2 and P3 are blue -shifted. The solution- processed organic field -effect transistors (OFETs) were fabricated with bottom gate/top contact geometry . The highest FET hole mobility of P3 after thermal annealing at 180 o C for 30 min reached 0.032 cm 2 /Vs with the on/ off ratio of 10 5 , which is a high value for the conjugated polymers . Polymer solar cells base on the polymers were fabricated , the power conversion efficiency of the devices based on P1 , P2 and P3 was 0.19%, 0.17% and 0.28%, respectively, under the illumination of AM1.5, 100 mW/cm 2 . The efficiency of the device based on P3 is ca. 50% higher than that of the devices based on P1 a nd P2 , which could be benefited from the higher hole mobility of P3 .

Soluble conjugated alternating porphyrin−dithienothiophene copolymers—single-bond linked (I) and triple-bond linked (IIa and IIb)—were synthesized by palladium(0)-catalyzed Stille and Sonagashira coupling reactions, respectively. The thermal, electrochemical, optical, charge transport, and photovoltaic properties of these copolymers were examined; the effect of the triple bond was studied. I exhibits onset decomposition temperature (Td) of 410 °C and glass-transition temperature (Tg) of 180 °C, higher than those of IIb (Td, 330 °C; Tg, 130 °C). The absorption spectrum of I in thin film exhibits a sharp Soret band at 450 nm and two weak Q-bands at 563−619 nm, while IIb exhibits a sharp Soret band at 491 nm and a strong Q-band at 760 nm. The emission maxima of I and IIb in solution are located at 642 and 722 nm respectively. IIb is electrochemically active in both the oxidation and reduction regions, while I shows only oxidation peak. The field-effect hole mobilities as high as 2.1 × 10−4 cm2 V−1 s−1 were o...

A new polythiophene derivative with phenothiazine-vinylene (PTZ V) conjugated side chains, PTZV-PT , was synthesized through the Stille coupling reaction, and characterized by 1 H NMR, elemental analysis, GPC, TGA, DSC, UV-vis absorption spectroscopy, photoluminescence spectroscopy and cyclic voltamm etry. The polymer is soluble in common organic solvents and possesses good thermal s tability with 5% weight loss at the temperature of 397°C and T g of 140°C. The weight-average molecular weight of PTZV-PT was 5.45 × 10 4 with the polydispersity index of 1.48. The absorption spectrum of PTZV-PT film displays a broad plateau between 300 and 600 nm. The hole mobility of PTZV-PT determined from space-charge-limited current model was 4.7 × 10 -3 cm 2 V -1 s -1 . The field effect hole mobility of the copolymer was as high as 6.8 × 10 -3 cm 2 ·V -1 s -1 with an on/off ratio of 2.5 × 10 4 , which is among the best performance of the copolymers reported for the solution-process ed organic field effect transistors (OFETs). The preliminary results indicate that PTZV-PT is a promising polymer material for applications in solution-processable OFETs .

Two series of polyurethanes (P1−P10) containing NLO chromophores as side chains were prepared, in which the size of isolation groups was changed from small atoms to much larger groups such as carbazolyl groups. The polymers were well characterized. The tested NLO properties of the polymers demonstrate that the NLO values and the poling efficiency of the polymers are not always improved with increasing of the size of isolation spacer, and for a given chromophore moiety, there is a suitable isolation group present to boost its microscopic β value to possibly higher macroscopic NLO property efficiently.

A new series of polyquinoline copolymers (P1−P5) containing 9,9‘-spirobifluorene in the main chain were synthesized via Friedlander reactions. The emission colors of the polymers were readily tuned from blue to yellow by changing the conjugated counits. Excellent EL performances were obtained for P5, probably because the proper donor/acceptor pairs were rightly matched, and the charge transport was significantly balanced. The devices based on P5 showed a maximum external quantum efficiency of 0.63% and a maximum photometric efficiency of 1.85 cd/A (at a brightness of 140 cd/m2). Yellow-green EL with narrow full width at the half-maximum (fwhm < 70 nm) and the highest maximum luminance (1768 cd/m2) among the currently reported polyquinolines was obtained for P5.

A novel series of conjugated copolymers having oxadiazole, quinoline, quinoxaline, and phenylenecyanovinylene moieties in the main chain based on fluorene were synthesized in good yields by palladium-catalyzed Suzuki coupling reaction, a new approach different from the traditional polyhydrazide precursor route (oxadiazole-containing polymers), acid-catalyzed Friedlander condensation reaction (polyquinolines), and Knoevenagel condensation polymerization (poly(phenylenecyanovinylene)). The thermal, electrochemical, and optical properties of these copolymers were examined. All these polymers possess excellent thermal stability with glass transition temperatures of 114−208 °C and onset decomposition temperatures of 387−415 °C. Cyclic voltammetry studies reveal that these copolymers possess low-lying LUMO energy levels ranging from −3.01 to −3.37 eV and low-lying HOMO energy levels ranging from −6.13 to −6.38 eV and may be promising candidates for electron-transporting or hole-blocking materials in light-emitt...