- Chemical oxidative and solid state synthesis of low molecular weight polymers for organic field effect transistors
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Solution processability of the precursor molecules is a major issue owing to their limited solubility for the synthesis of conjugated polymers. Therefore, we favour the solvent free solid state chemical oxidative polymerization route for the synthesis of diketopyrrolopyrrole (DPP) based donor-acceptor (D-A) type conjugated polymers. D-A type polymer Poly(S-OD-EDOT) which contains DPP coupled with EDOT donor units is synthesized via solid state polymerization method. The polymer is employed as an active layer for organic field-effect transistors to measure charge transport properties. The Polymer shows good hole mobility 3.1 × 10?2 cm2 V?1 s?1, with a on/off ratio of 1.1 × 103.
- Mahale, Rajashree Y.,Dharmapurikar, Satej S.,Chini, Mrinmoy Kumar
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- Annealing-free high-mobility diketopyrrolopyrrole-quaterthiophene copolymer for solution-processed organic thin film transistors
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A donor-acceptor polymer semiconductor, PDQT, comprising diketopyrrolopyrrole (DPP) and β-unsubstituted quaterthiophene (QT) for organic thin film transistors (OTFTs) is reported. This polymer forms ordered layer-by-layer lamellar packing with an edge-on orientation in thin films even without thermal annealing. The strong intermolecular interactions arising from the fused aromatic DPP moiety and the DPP-QT donor-acceptor interaction facilitate the spontaneous self-assembly of the polymer chains into close proximity and form a large π-π overlap, which are favorable for intermolecular charge hopping. The well-interconnected crystalline grains form efficient intergranular charge transport pathways. The desirable chemical, electronic, and morphological structures of PDQT bring about high hole mobility of up to 0.97 cm2/(V·s) in OTFTs with polymer thin films annealed at a mild temperature of 100 °C and similarly high mobility of 0.89 cm2/(V·s) for polymer thin films even without thermal annealing.
- Li, Yuning,Sonar, Prashant,Singh, Samarendra P.,Soh, Mui Siang,Van Meurs, Martin,Tan, Jozel
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- 2,5-bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4-(2H,5H)-dione-based donor-acceptor alternating copolymer bearing 5,5′-Di(thiophen-2-yl)-2, 2′-biselenophene exhibiting 1.5 cm2·V -1·s-1 hole mobility in thin-film transistors
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A novel diketopyrrolopyrrole-based π-conjugated copolymer P(DPP-alt-DTBSe), 5, and a known copolymer P(DPP-alt-QT), 4, have been synthesized in 80-90% yield using the Stille coupling reaction. The molecular weights of 4 and 5 are 58 781 and 19 271 g/mol, respectively, with polydispersity values of 3.25-3.35. A relatively small band gap of 1.32-1.39 eV and excellent solubility in organic solvents were achieved in the two polymers. Thin-film transistors made of 5 exhibit outstanding performance (e.g., μ > 1.0-1.5 cm2·V-1·s-1, I on/Ioff > 105-106) with a conventional n-octyltrichlorosilane-SiO2 gate dielectric.
- Ha, Jae Seung,Kim, Kyung Hwan,Choi, Dong Hoon
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- Modulation of electronic properties of π-conjugated copolymers derived from naphtho[1,2-b:5,6-b′]dithiophene donor unit: A structure-property relationship study
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A set of three donor-acceptor conjugated (D-A) copolymers were designed and synthesized via Stille cross-coupling reactions with the aim of modulating the optical and electronic properties of a newly emerged naphtho[1,2-b:5,6-b′] dithiophene donor unit for polymer solar cell (PSCs) applications. The PTNDTT-BT, PTNDTT-BTz, and PTNDTT-DPP polymers incorporated naphtho[1,2-b:5,6- b′]dithiophene (NDT) as the donor and 2,2′-bithiazole (BTz), benzo[1,2,5]thiadiazole (BT), and pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP), as the acceptor units. A number of experimental techniques such as differential scanning calorimetry, thermogravimetry, UV-vis absorption spectroscopy, cyclic voltammetry, X-ray diffraction, and atomic force microscopy were used to determine the thermal, optical, electrochemical, and morphological properties of the copolymers. By introducing acceptors of varying electron withdrawing strengths, the optical band gaps of these copolymers were effectively tuned between 1.58 and 1.9 eV and their HOMO and LUMO energy levels were varied between -5.14 to -5.26 eV and -3.13 to -3.5 eV, respectively. The spin-coated polymer thin film exhibited p-channel field-effect transistor properties with hole mobilities of 2.73 × 10-3 to 7.9 × 10-5 cm2 V-1 s-1. Initial bulk-heterojunction PSCs fabricated using the copolymers as electron donor materials and [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) as the acceptor resulted in power conversion efficiencies in the range of 0.67-1.67%.
- Dutta, Pranabesh,Park, Hanok,Oh, Minjae,Bagde, Sushil,Kang, In Nam,Lee, Soo-Hyoung
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- Processing temperature control of a diketopyrrolopyrrole-alt-thieno[2,3-b]thiophene polymer for high-mobility thin-film transistors and polymer solar cells with high open-circuit voltages
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We synthesized a planar pDPPTTi-OD polymer based on diketopyrrolopyrrole (DPP) and thieno [2,3-b]thiophene (TTi) and investigated the electrical properties of the pDPPTTi-OD polymer. pDPPTTi-OD films displayed a low optical bandgap of 1.57?eV, and HOMO and LUMO levels of??5.40 and??3.74?eV, respectively. The 150°C-annealed pDPPTTi-OD films showed a high hole mobility of 0.16?cm2V?1s?1 in organic thin-film transistor (OTFT) devices. The photovoltaic properties of polymer solar cells (PSCs) incorporating the pDPPTTi-OD were also measured. A pDPPTTi-OD:PC71BM blend film was spin-coated at 25, 70 and 90?°C. High-temperature processing significantly improved the power conversion efficiency of PSCs by effectively reducing the PC71BM domain sizes, which improved the miscibility between pDPPTTi-OD and PC71BM. This work demonstrated that the TTi moiety is a useful donor building block for high- performance D–A type polymers in OTFTs and PSCs, and that processing temperatures should be controlled to fully realize the materials’ beneficial intrinsic properties.
- Lee, Hyo-Sang,Lee, Joong Suk,Jung, A-Ra,Cha, Wonsuk,Kim, Hyunjung,Son, Hae Jung,Cho, Jeong Ho,Kim, BongSoo
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- Photocontrolled Synthesis of n-Type Conjugated Polymers
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Current approaches to synthesize π-conjugated polymers (CPs) are dominated by thermally driven, transition-metal-mediated reactions. Herein we show that electron-deficient Grignard monomers readily polymerize under visible-light irradiation at room temperature in the absence of a catalyst. The product distribution can be tuned by the wavelength of irradiation based on the absorption of the polymer. Conversion studies are consistent with an uncontrolled chain-growth process; correspondingly, chain extension produces all-conjugated n-type block copolymers. Preliminary results demonstrate that the polymerization can be expanded to donor–acceptor alternating copolymers. We anticipate that this method can serve as a platform to access new architectures of n-type CPs without the need for transition-metal catalysis.
- Berl, Alexandra J.,Kalow, Julia A.,Woods, Eliot F.
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- A timely synthetic tailoring of biaxially extended thienylenevinylene-like polymers for systematic investigation on field-effect transistors
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Considering there is growing interest in the superior charge transport in the ( E )-2-(2-(thiophen-2-yl)-vinyl)thiophene (TVT)-based polymer family, an essential step forward is to provide a deep and comprehensive understanding of the structure-property relationships with their polymer analogs. Herein, a carefully chosen set of DPP-TVT-n polymers are reported here, involving TVT and diketopyrrolopyrrole (DPP) units that are constructed in combination with varying thiophene content in the repeat units, where n is the number of thiophene spacer units. Their OFET characteristics demonstrate ambipolar behavior; in particular, with DPP-TVT-0 a nearly balanced hole and electron transport are observed. Interestingly, the majority of the charge-transport properties changed from ambipolar to p-type dominant, together with the enhanced hole mobilities, as the electron-donating thiophene spacers are introduced. Although both the lamellar d-spacings and π-stacking distances of DPP-TVT-n decreased with as the number of thiophene spacers increased, DPP-TVT-1 clearly shows the highest hole mobility (up to 2.96 cm2 V-11 s-1) owing to the unique structural conformations derived from its smaller paracrystalline distortion parameter and narrower plane distribution relative to the others. These in-depth studies should uncover the underlying structure-property relationships in a relevant class of TVT-like semiconductors, shedding light on the future design of top-performing semiconducting polymers.
- Yoo, Dohyuk,Nketia-Yawson, Benjamin,Kang, Seok-Ju,Ahn, Hyungju,Shin, Tae Joo,Noh, Yong-Young,Yang, Changduk
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- Effects of Chemical Composition, Film Thickness, and Morphology on the Electrochromic Properties of Donor-Acceptor Conjugated Copolymers Based on Diketopyrrolopyrrole
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A series of diketopyrrolopyrrole (DPP) and propylenedioxythiophene (ProDOT)-containing random copolymers with different donor-to-acceptor ratios is synthesized through Stille coupling polymerizations. The low-bandgap polymers display dark tones with colors ranging from magenta to blue, and reveal reversible colored-to-transmissive electrochromism in absorption/transmission-type devices with high optical contrasts (up to 48 and 77 in the visible and near-infrared regions, respectively), modest switching speeds (a few to tens of seconds) and coloration efficiencies (267-5742C-1), as well as good long-term ambient redox stabilities. The structure-performance relationship of the polymers, in particular, the role of donor-to-acceptor ratio, is investigated, and it is shown that an increase in the amount of acceptor in the polymers leads to slower oxidative but faster reductive switching, accompanied with enhancement of the redox stability. In addition, further study on the influence of film thickness and film morphology reveals that devices with higher optical contrasts are attainable from thicker polymer films at the expense of switching speeds; films with high uniformity and connectedness together with open, loose structures at submicron to micron scale are favorable for achieving good electrochromic performance. On and off: A series of electrochromic diketopyrrolopyrrole-based conjugated polymers are synthesized and characterized. Reversible colored-to-transmissive optical changes with high contrasts and ambient redox stabilities are observed (see figure). The influences of donor-to-acceptor ratio and film morphology on the electrochromic performance are addressed.
- Neo, Wei Teng,Shi, Zugui,Cho, Ching Mui,Chua, Soo-Jin,Xu, Jianwei
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- Novel 4,8-benzobisthiazole copolymers and their field-effect transistor and photovoltaic applications
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A series of copolymers containing the benzo[1,2-d:4,5-d′]bis(thiazole) (BBT) unit has been designed and synthesised with bisthienyl-diketopyrrolopyrrole (DPP), dithienopyrrole (DTP), benzothiadiazole (BT), benzodithiophene (BDT) or 4,4′-dialkoxybithiazole (BTz) comonomers. The resulting polymers possess a conjugation pathway that is orthogonal to the more usual substitution pathway through the 2,6-positions of the BBT unit, facilitating intramolecular non-covalent interactions between strategically placed heteroatoms of neighbouring monomer units. Such interactions enable a control over the degree of planarity through altering their number and strength, in turn allowing for tuning of the band gap. The resulting 4,8-BBT materials gave enhanced mobility in p-type organic field-effect transistors of up to 2.16 × 10-2 cm2 V-1 s-1 for pDPP2ThBBT and good solar cell performance of up to 4.45% power conversion efficiency for pBT2ThBBT.
- Conboy, Gary,Taylor, Rupert G. D.,Findlay, Neil J.,Kanibolotsky, Alexander L.,Inigo, Anto R.,Ghosh, Sanjay S.,Ebenhoch, Bernd,Krishnan Jagadamma, Lethy,Thalluri, Gopala Krishna V. V.,Sajjad, Muhammad T.,Samuel, Ifor D. W.,Skabara, Peter J.
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p. 11927 - 11936
(2017/11/30)
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- NOVEL COMPOUND AND PHOTOELECTRIC CONVERSION DEVICE HAVING THE SAME
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The present specification of the photoelectric conversion element is the life, efficiency, electrochemical stability and thermal stability can be compound, said compound number. under public affairs including photoelectric conversion element. Specifically photoelectric conversion region of. under public affairs number organic solar cell. (by machine translation)
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Paragraph 0197-0199
(2017/04/21)
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- Correlation of structure and photovoltaic performance of benzo[1,2-b:4,5-b′]dithiophene copolymers alternating with different acceptors
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Four π-conjugated benzo[1,2-b:4,5-b′]dithiophene (BDT) based polymers were synthesized for application in polymer solar cells. These polymers possessed desirable HOMO/LUMO levels for polymer photovoltaic applications. PBDTT-TTz and PBDTT-DTBT displayed strong absorption in the range of 300-650 nm, while PBDTT-DPP and PBDTT-TTDPP showed a further 100 nm extended absorption band. The lowest unoccupied molecular orbital energy levels of polymers were tuned effectively from -3.34 eV to -3.81 eV by fusing with different accepting units. A maximum power conversion efficiency of 2.60% was obtained from photovoltaic cells with a PBDTT-TTz:PC61BM (1:2, w/w) blend film as the active layer, with a short circuit current density of 8.37 mA cm-2, an open circuit voltage of 0.70 V, and a fill factor of 44.3%. This journal is
- Yu, Jiangsheng,Zhao, Baofeng,Nie, Xuemei,Zhou, Baojin,Li, Yang,Hai, Jiefeng,Zhu, Enwei,Bian, Linyi,Wu, Hongbin,Tang, Weihua
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p. 2248 - 2255
(2015/03/18)
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- Low band-gap diketopyrrolopyrrole-containing polymers for near infrared electrochromic and photovoltaic applications
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Donor-acceptor type polymers bearing diketopyrrolopyrrole and 3,4-ethylenedioxythiophene units are reported. The polymers are green and exhibit very low band-gaps (1.19 eV) with strong and broad absorption (maxima of about 830 nm) in the near infrared (NI
- Low, Jonathan Zhaozhi,Neo, Wei Teng,Ye, Qun,Ong, Wen Jie,Wong, Ivy Hoi Ka,Lin, Ting Ting,Xu, Jianwei
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p. 1287 - 1295
(2015/04/14)
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- Synthesis and optical properties of photovoltaic materials based on the ambipolar dithienonaphthothiadiazole unit
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Dithieno[3′2′:5,6;2′′,3′′:7,8]naphtho[2,3-c][1,2,5]thiadiazole (DTNT) was designed to control the band energies of the polymers for photovoltaic materials. Electrochemical analysis showed that DTNT acts as both an electron donor and an electron acceptor, revealing the ambipolar nature of the DTNT unit. The direct arylation polymerization of DTNT with 2,2′-bithiophene (BTh) and 3,6-bis(2-thienyl)pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) afforded four polymers that differed in either the unit of copolymerization or the chosen side chains. In the PDTNT-BTh series, a shoulder absorption band was observed at a longer wavelength than the intense absorption band. The PDTNT-DPP series exhibited a narrow band gap of less than 1.4 eV and a low HOMO energy of -5.43 eV. An organic photovoltaic cell that contained a PDTNT-BTh polymer with 2-ethylhexyl groups and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an active layer afforded the best performance among the studied compounds, with a JSC of 6.98 mA cm-3, a VOC of 0.758 V, a FF of 0.52, and a PCE of 2.76%.
- Nakanishi, Tatsuaki,Shirai, Yasuhiro,Han, Liyuan
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p. 4229 - 4238
(2015/03/04)
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- Influence of side chain length and bifurcation point on the crystalline structure and charge transport of diketopyrrolopyrrole-quaterthiophene copolymers (PDQTs)
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The influence of the side chain on the molecular organization and charge transport performance of diketopyrrolopyrrole-quaterthiophene copolymers (PDQTs) was studied. It was found that, by increasing the side chain length from 2-octyldodecyl (PDQT-20) to 2-decyltetradecyl (PDQT-24), the mobility increased from 2.10 cm2 V-1 s-1 up to 3.37 cm2 V-1 s-1 in organic thin film transistors (OTFTs). The increase was found to be due to the improved surface morphology, rather than the changes in crystallinity and π-π stacking distance. A new side chain substituent, 4-decylhexadecyl, was developed for studying the effects of the bifurcation point of the branched side chains in comparison with 2-octyldodecyl and 2-decyltetradecyl. The 4-decylhexadecyl substituted PDQT (PDQT-26) showed a surge in mobility up to 6.90 cm2 V-1 s-1. The remarkably enhanced charge transport performance observed for PDQT-26 was believed to originate from its much shorter π-π distance (3.68 A) than those of PDQT-20 (3.79 A) and PDQT-24 (3.86 A). The improvement was the result of a farther distance of the bifurcation point of 4-decylhexadecyl from the polymer backbone, which could effectively minimize the steric interference of the bulky side chain branches with the backbone to facilitate the co-facial π-π stacking.
- Chen, Shaoyun,Sun, Bin,Hong, Wei,Aziz, Hany,Meng, Yuezhong,Li, Yuning
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p. 2183 - 2190
(2014/03/21)
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- Use of side-chain for rational design of n-type diketopyrrolopyrrole-based conjugated polymers: What did we find out?
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The primary role of substituted side chains in organic semiconductors is to increase their solubility in common organic solvents. In the recent past, many literature reports have suggested that the side chains play a critical role in molecular packing and strongly impact the charge transport properties of conjugated polymers. In this work, we have investigated the influence of side-chains on the charge transport behavior of a novel class of diketopyrrolopyrrole (DPP) based alternating copolymers. To investigate the role of side-chains, we prepared four diketopyrrolopyrrole-diketopyrrolopyrrole (DPP-DPP) conjugated polymers with varied side-chains and carried out a systematic study of thin film microstructure and charge transport properties in polymer thin-film transistors (PTFTs). Combining results obtained from grazing incidence X-ray diffraction (GIXD) and charge transport properties in PTFTs, we conclude side-chains have a strong influence on molecular packing, thin film microstructure, and the charge carrier mobility of DPP-DPP copolymers. However, the influence of side-chains on optical properties was moderate. The preferential "edge-on" packing and dominant n-channel behavior with exceptionally high field-effect electron mobility values of >1 cm2 V-1 s-1 were observed by incorporating hydrophilic (triethylene glycol) and hydrophobic side-chains of alternate DPP units. In contrast, moderate electron and hole mobilities were observed by incorporation of branched hydrophobic side-chains. This work clearly demonstrates that the subtle balance between hydrophobicity and hydrophilicity induced by side-chains is a powerful strategy to alter the molecular packing and improve the ambipolar charge transport properties in DPP-DPP based conjugated polymers. Theoretical analysis supports the conclusion that the side-chains influence polymer properties through morphology changes, as there is no effect on the electronic properties in the gas phase. The exceptional electron mobility is at least partially a result of the strong intramolecular conjugation of the donor and acceptor as evidenced by the unusually wide conduction band of the polymer. the Partner Organisations 2014.
- Kanimozhi, Catherine,Yaacobi-Gross, Nir,Burnett, Edmund K.,Briseno, Alejandro L.,Anthopoulos, Thomas D.,Salzner, Ulrike,Patil, Satish
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p. 17253 - 17265
(2014/08/05)
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- Diketopyrrolopyrrole-Thiophene-Benzothiadiazole random copolymers: An effective strategy to adjust thin-film crystallinity for transistor and photovoltaic properties
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Three new low bandgap conjugated random copolymers, containing two acceptors diketopyrrolopyrrole (DPP) and benzothiadiazole (BTD) linked by thiophene donors, were designed and synthesized using Pd-catalyzed Stille-coupling methods. The ratio between DPP and BTD was varied from N = 3:7 to 1:1 to 7:3 in the polymer backbones. Thin-film device measurements indicate that these polymers exhibit different trends in field-effect mobilities and photovoltaic properties owing to adjustable nanoscale film morphologies as well as solid-state molecular packing. The hole mobilities reach 0.05, 0.17, and 0.40 cm2 V-1 s-1 for N = 3:7, 1:1, and 7:3 copolymers while bulk heterojuction solar cells fabricated by using N = 3:7, 1:1, and 7:3 copolymers as donor and PC60BM as acceptor show power conversion efficiency of 2.4%, 1.3%, and 0.5%. This work sets up a good example of effectively tuning the crystallinity of thin-film device through easily varying the composition ratios.
- Li, Hui,Liu, Fangbin,Wang, Xuedong,Gu, Chunling,Wang, Ping,Fu, Hongbing
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p. 9211 - 9219
(2014/01/06)
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- Importance of solubilizing group and backbone planarity in low band gap polymers for high performance ambipolar field-effect transistors
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We investigated the performance of ambipolar field-effect transistors based on a series of alternating low band gap polymers of oligothiophene and diketopyrrolopyrrole (DPP). The polymers contain oligothiophene units of terthiophene [T3] and thiophenethienothiophene-thiophene [T2TT] and DPP units carrying branched alkyl chains of 2-hexyldecyl [HD] or 2-octyldodecyl [OD]. The structural variation allows us to do a systematic study on the relationship between the interchain stacking/ordering of semiconducting polymers and their resulting device performance. On the basis of synchrotron X-ray diffraction and atomic force microscopy measurements on polymer films, we found that longer branched alkyl side chains, i.e., OD, and longer and more planar oligothiophene, i.e., T2TT, generate the more crystalline structures. Upon thermal annealing, the crystallinity of the polymers was largely improved, and polymers containing a longer branched alkyl chain responded faster because longer alkyl chains have larger cohesive forces than shorter chains. For all the polymers, excellent ambipolar behavior was observed with a maximum hole and electron mobility of 2.2 and 0.2 cm2 V-1 ss, respectively.
- Lee, Joong Suk,Son, Seon Kyoung,Song, Sanghoon,Kim, Hyunjung,Lee, Dong Ryoul,Kim, Kyungkon,Ko, Min Jae,Choi, Dong Hoon,Kim, Bong Soo,Cho, Jeong Ho
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p. 1316 - 1323
(2012/08/28)
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