Search

A fascinating multifunctional screen window containing air filtration, rain-flow transportation and photochromic functions.

The advocacy of smart living results in a high demand for wearable and flexible sensors to monitor human motions. Among these, sensors based on strain–optics conversion are attractive due to their ...

Organic conjugated porous polymers, triazine-Ph-CPP and triazine-Th-CPP, are synthesized and characterized. Without further addition of co-catalysts, triazine-Ph-CPP exhibits a HER of 16 287 μmol g−1 h−1 and an apparent quantum yield of 61.5% at 365 nm, which demonstrates that the dibenzo[b,d]thiophene sulfone and 1,3,5-triazine based polymer is a unique prototype of a highly efficient hydrogen evolution photocatalyst.

Halogen-halogen (X···X) interaction is a kind of strong intermolecular interaction. This interaction has great impact on the aggregation structures and optoelectronic properties of organic π-conjugated molecules. However, it is still a great challenge to tune the X···X interactions among organic π-conjugated molecules. In this article, with trans -stilbene as an example, the regulation of halogen-halogen interactions between organic π-conjugated molecules is achieved through chemical structure modification, that is introducing electron-donating methylthio group and changing the position of halogen substituents on trans -stilbene skeleton. The influence of halogen-halogen interactions on the aggregation structure and luminescence properties of trans -stilbenes was investigated.

It is a very important and challenging topic to design high performance n-channel organic semiconductors with a new type conjugated skeleton. Herein, a new class of n-channel organic semiconductors, pyrrolo[3,2-b]pyrrole-based quinoidal molecules QBPBP and QFBPBP, was designed and synthesized. Both compounds have low-lying lowest unoccupied molecular orbital energy level and high thermal stability. Single crystal structures reveal they adopt unusual two-dimensional layer-type packing structures in single crystals. Multiple π–π and CN···H interactions are observed in the layer, and alkyl–alkyl chain interactions exist between layers. Transistors based on single ribbons displayed gate voltage-dependent electron mobility with an average of 4.0 cm2 V–1 s–1 and a peak over 6.0 cm2 V–1 s–1 under N2. These results demonstrate pyrrolo[3,2-b]pyrrole-based quinoidal molecules are a new prototype for high performance n-channel organic semiconductors.

Due to their strong intermolecular interactions, polymer semiconductors aggregate in solution even at elevated temperature. With the aim to study the effect of this kind preaggregation on the order of thin films and further transistor performance, bi-thieno[3,4-c]pyrrole-4,6-dione and fluorinated oligothiophene copolymerized polymer semiconductor P1, which shows strong temperature-dependent aggregation behavior in solution, is synthesized. Its films are deposited through a temperature-controlled dip-coating technique. X-ray diffraction and atomic force microscopy results reveal that the aggregation behavior of P1 in solution affects the microstructures and order of P1 films. The charge transport properties of P1 films are investigated with bottom-gate top-contacted thin-film transistors. The variation of device performance (from 0.014 to 1.03 cm2 V–1 s–1) demonstrates the importance of optimizing preaggregation degree. The correlation between preaggregation degree and transistor performance of P1 films is explored.

Bi-thieno[3,4]pyrrole-4,6-dione (bi-TPD) based copolymers containing 1,2-bis(2-thienyl)ethene (P1) and 1,2-diphenylethene (P2) units are synthesized and characterized. Their physicochemical and electrical properties as well as molecular packing structures in thin films have been fully investigated. P1 has higher HOMO energy levels and smaller bandgap than P2, which is attributed to the stronger electron-donating ability of 1,2-bis(2-thienyl)ethene unit. Both polymers form continuous films and adopt face-on and edge-on co-orientation in the aggregation states. The crystallinity of P1 film is higher than that of P2 film. The optimal field-effect mobility is 0.74 cm2V−1s−1 for P1 films and 0.32 cm2V−1s−1 for P2 films. These results demonstrated the merits of 1, 2-bis(2-thienyl)ethene unit and the potential applications of bi-TPD based polymers in high performance polymer transistors.

Bithienopyrroledione (bi-TPD) based polymers P1 and P2 are designed and synthesized. Photovoltaic devices based on P1:PC71BM and P2:PC71BM blend films show power conversion efficiencies (PCEs) of 8.22% and 9.08%, respectively, whereas devices based on their thienopyrroledione (TPD)-based analogue P3 and PC71BM blend films display a PCE of 5.10%.

The novel dicyanomethylene-substituted 1,2-bis(thieno[3,2-b]thiophene-2-yl)ethene based quinoidal compounds QBTTE and F2-QBTTE are reported. The F⋯H (vinylene) hydrogen bonds lock the backbone conformation and greatly improve the transistor performance of F2-QBTTE.

Acceptor-donor-acceptor type compounds W1–W3 were designed and synthesized. These compounds had the same donor moiety of 2,6-di(thiophen-2-yl)dithieno[3,2-b:2′,3′-d]thiophene and different acceptor groups of 2-dicyanomethylen-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran (TCF), dicyanovinyl (DCV) and 3-ethyl-2-thioxothiazolidin-4-one. Experimental results showed all compounds had high thermal stability and strong absorption in the visible light region. Among them, compound W1 with TCF as acceptor group displayed the lowest LUMO energy level of −3.74 eV and the smallest HOMO-LUMO band gap of 1.74 eV, suggesting the potential applications of TCF unit in low band gap organic semiconductors.

A solution-processable tetrathienoquinoidal semiconductor CMHT was synthesized and characterized. Single crystal diffraction results showed that CMHT adopted slipped π–π stacking in the crystal structure. Multiple intermolecular interactions, such as S⋯N and S⋯C (where C is the carbon on the cyano group), existed among neighboring molecules, which formed a 2-dimensional charge transport network. Solution-processed thin film transistors of CMHT displayed a high electron mobility of up to 0.22 cm2 V−1 s−1 under ambient conditions, one of the highest electron mobilities for quinoidal semiconductors. The correlation between the molecular packing of the CMHT and transistor performance was studied by AFM and XRD.

We herein report on an efficient synthesis of diacenaphthylene-fused benzo[1,2-b:4,5-b′]dithiophenes and demonstrate that their packing structure in the solid state depends on the substituent groups. These compounds form dimers with their radical cations in high concentration solution and exhibit good field-effect mobility.

The film morphology, structure, and electrical properties of lead phthalocyanine (PbPc) epitaxially grown on 5,5 ''-bis(3'-fluoro-biphenyl-4-yl)-2,2':5',2 ''-terthiophene (m-F2BP3T) inducing layer substrates were systematic investigated. The morphologies of PbPc films sensitively depend on the thickness of the inducing layer and substrate temperature. All the epitaxial PbPc films with high quality presented the triclinic form with a variation of the out-of-plane orientation. The field-effect mobility of the epitaxial PbPc films was 0.05-0.31 cm(2)/V s, which was significantly improved by 1-2 orders of magnitude compared to the traditional films. The evolution of the device performance is the synergistic effect of the morphology and out-of-plane orientation of the triclinic form of PbPc. The higher quality of the films and the smaller ratio of (100)/(001), the higher device performance is. A clear relationship between the morphology, structure, and the performance of epitaxial PbPc-based organic field-effect transistors was reported. (C) 2012 Elsevier B.V. All rights reserved.

Efficient planar organic solar cells extending the response into the near-infrared (NIR) were fabricated using the highly ordered Titanyl phthalocyanines (TiOPc) films as the donor layer. This type of films obtained through the weak epitaxy growth (WEG) method presents good continuity and integrity with the low density of grain boundaries. More importantly the films own a strong absorption in the NIR (750-950 nm) and a broad absorption spectrum from 550 to 950 nm. Meanwhile the high external quantum efficiency (EQE) is obtained in the NIR with the peak value over 38% and the EQE is over 18% in the entire response range, which could benefit from the long exciton diffusion length and the high carrier mobility of the highly ordered films. Thereby the fabricated planar solar cells achieve a high short-circuit current density (J(sc)) of 9.26 mA cm(-2) and a power conversion efficiency (PCE) of 2.67%. (C) 2012 Elsevier B.V. All rights reserved.

A donor–acceptor–donor (D–A–D) type small molecule DHB-QDTB, with dicyano-substituted quinoidal benzo[1,2-b:4,5-b′]dithiophene as the acceptor, was designed and synthesized. A high electron mobility up to 0.88 cm2 V−1 s−1 was observed for DHB-QDTB based transistors under ambient conditions, suggesting quinoidal benzo[1,2-b:4,5-b′]dithiophene is an excellent acceptor unit in D–A type n-channel organic semiconductors.

A novel solution-processable dicyano-substituted quinoidal oligothiophene molecule CDT-2T(CN)4 was synthesized and characterized. CDT-2T(CN)4 displayed high thermal stability and broad thin film absorption in the near IR region. Electrochemical results showed that CDT-2T(CN)4 exhibited reversible oxidation and reduction peaks with the LUMO energy level at −4.2 eV and the HOMO energy level at −5.3 eV. The solution processed thin film transistors of CDT-2T(CN)4 displayed electron-dominant ambipolar transport behavior under ambient conditions. The optimal saturation hole and electron mobilities were 0.003 and 0.023 cm2 V−1 s−1, respectively, one of the highest values for solution processed quinoidal based ambipolar organic semiconductors with good ambient stability.