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Zhang G.,Academy of Opto Electronic Technology | Fu Y.,CAS Changchun Institute of Applied Chemistry | Qiu L.,Academy of Opto Electronic Technology | Xie Z.,CAS Changchun Institute of Applied Chemistry
Polymer (United Kingdom) | Year: 2012

New random poly{benzo[1,2-b:4,5-b']dithiophene-thieno[3,4-c]pyrrole-4,6- dione-pyrrolo[3,4-c]pyrrole-1,4-dione} (PBDT-TPD-DPP) based on benzo[1,2-b:4,5-b']dithiophene (BDT) as donor and thieno[3,4-c]pyrrole-4,6-dione (TPD, 60-90%), pyrrolo[3,4-c]pyrrole-1,4-dione (DPP, 10-40%) as acceptors were synthesized through Stille coupling reaction. The photophysical, electrochemical and photovoltaic properties of random polymers were investigated. The random polymers with high molecular weight (M n = 33.5-41.7 kDa) exhibited broad and strong absorption covering the spectra range from 350 nm up to 922 nm with absorption maxima at around 700 nm, the relatively deep highest occupied molecular orbital (HOMO) energy levels vary between -5.25 and -5.42 eV and suitable lowest unoccupied molecular orbital (LUMO) energy levels ranging from -3.85 to -3.91 eV. Polymer solar cells (PSC) based on these new random polymers were fabricated with device structures of ITO/PEDOT: PSS/random polymers: PC 71BM (1:2, w/w)/Ca/Al. The photovoltaic properties of random polymers were evaluated under AM 1.5G illumination (100 mW/cm 2). Devices based on the random polymers showed open circuit voltage (V oc) of 0.71-0.83 V, and power conversion efficiency (PCE) of 0.82-1.80%. © 2012 Elsevier Ltd. All rights reserved.

Zhang G.,Academy of Opto Electronic Technology | Peng R.,Academy of Opto Electronic Technology | Li P.,Academy of Opto Electronic Technology | Wang X.,Academy of Opto Electronic Technology | And 3 more authors.
Synthetic Metals | Year: 2013

Thieno[3,4-c]pyrrole-4,6-dione (TPD)-based polymer (PDTTPD) with head-to-head (H-H) linkage of 3-dodecylthiophene unit was synthesized by ferric chloride oxidative polymerization. The polymer was characterized by chemical analysis as well as thermal analysis, optical spectroscopy and cyclic voltammeter. PDTTPD polymer showed excellent thermal stability, had significantly red-shifted of absorption edge by its solid film compared to its solution and a deep highest occupied molecular orbital (HOMO) energy level of -5.82 eV. Polymer thin-film microstructures and morphologies were also investigated through atomic force microscope (AFM) and grazing-incidence X-ray diffraction (GIXD) which showed that the PDTTPD film is composed of rod-like crystalline grains and ordered structures. Organic thin-film transistors (OTFT) with common architectures were fabricated to evaluate OTFT performance and exhibited the preliminary hole mobility of 0.019 cm-2 V-1 s-1. © 2013 Elsevier B.V. All rights reserved.

Wang X.,Academy of Opto Electronic Technology | Yuan M.,Academy of Opto Electronic Technology | Yuan M.,Hefei University of Technology | Xiong X.,Academy of Opto Electronic Technology | And 8 more authors.
Thin Solid Films | Year: 2015

Inkjet printing of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-PEN), a small molecule organic semiconductor, is performed on two types of substrates. Hydrophilic SiO2 substrates prepared by a combination of surface treatments lead to either a smaller size or a coffee-ring profile of the single-drop film. A hydrophobic surface with dominant dispersive component of surface energy such as that of a spin-coated poly(4-vinylphenol) film favors profile formation with uniform thickness of the printed semiconductor owing to the strong dispersion force between the semiconductor molecules and the hydrophobic surface of the substrate. With a hydrophobic dielectric as the substrate and via a properly selected solvent, high quality TIPS-PEN films were printed at a very low substrate temperature of 35 °C. Saturated field-effect mobility measured with top-contact thin-film transistor structure shows a narrow distribution and a maximum of 0.78 cm2V- 1 s- 1, which confirmed the film growth on the hydrophobic substrate with increased crystal coverage and continuity under the optimized process condition. © 2015 Elsevier B.V. All rights reserved.

Wang X.,Academy of Opto Electronic Technology | Yuan M.,Academy of Opto Electronic Technology | Yuan M.,Hefei University of Technology | Lv S.,Academy of Opto Electronic Technology | And 6 more authors.
Journal of Applied Physics | Year: 2015

The performance of organic thin film transistors (OTFTs) is heavily dependent on the interface property between the organic semiconductor and the dielectric substrate. Device fabrication with bottom-gate architecture by depositing the semiconductors with a solution method is highly recommended for cost-effectiveness. Surface modification of the dielectric layer is employed as an effective approach to control film growth. Here, we perform surface modification via a self-assembled monolayer of silanes, a spin-coated polymer layer or UV-ozone cleaning, to prepare surfaces with different surface polarities and morphologies. The semiconductor is inkjet-printed on the surface-treated substrates as single-line films with overlapping drop assignment. Surface morphologies of the dielectric before film deposition and film morphologies of the inkjet-printed semiconductor are characterized with polarized microscopy and AFM. Electrical properties of the films are studied through organic thin-film transistors with bottom-gate/bottom-contact structure. With reduced surface polarity and nanoscale aggregation of silane molecules on the substrates, semiconductor nucleates from the interior interface between the ink solution and the substrate, which contributes to film growth with higher crystal coverage and better film quality at the interface. Surface treatment with hydrophobic silanes is a promising approach to fabrication of high performance OTFTs with nonpolar conjugated molecules via solution methods. © 2015 AIP Publishing LLC.

Peng R.,Academy of Opto Electronic Technology | Pang B.,Academy of Opto Electronic Technology | Hu D.,Academy of Opto Electronic Technology | Chen M.,Academy of Opto Electronic Technology | And 7 more authors.
Journal of Materials Chemistry C | Year: 2015

A novel semiconductor-rubber-semiconductor (P3HT-PMA-P3HT) triblock copolymer has been designed and prepared according to the principle of thermoplastic elastomers. It behaves as a thermoplastic elastomer with a Young's modulus (E) of 6 MPa for an elongation at break of 140% and exhibits good electrical properties with a carrier mobility of 9 × 10-4 cm2 V-1 s-1. This novel semiconductor may play an important role in low-cost and large-area stretchable electronics. © 2015 The Royal Society of Chemistry.

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