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ABSTRACT: A new anthracene-based X-shaped conjugated molecule, HBTATHT, was synthesized. Thin film transistors based on unannealed HBTATHT showed a carrier mobility of 0.15 cm(2) V(-1) s(-1) (I(on/off) = 7.9 × 10(6)). Further, a solution processed solar cell made of HBTATHT exhibited promising power conversion efficiencies of 4.84% and 4.70% with PC(61)BM (1:0.8 wt ratio) and PC(71)BM (1:0.6 wt ratio), respectively.
Chemical Communications 07/2012; 48(68):8490-2. · 6.17 Impact Factor
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Tae Wu Kim,
Jae Hyuk Lee,
Jungkweon Choi, Kyung Hwan Kim,
Luuk J van Wilderen,
Laurent Guerin,
Youngmin Kim,
Yang Ouk Jung,
Cheolhee Yang,
Jeongho Kim,
Michael Wulff,
Jasper J van Thor,
Hyotcherl Ihee
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ABSTRACT: Photoreceptor proteins play crucial roles in receiving light stimuli that give rise to the responses required for biological function. However, structural characterization of conformational transition of the photoreceptors has been elusive in their native aqueous environment, even for a prototype photoreceptor, photoactive yellow protein (PYP). We employ pump-probe X-ray solution scattering to probe the structural changes that occur during the photocycle of PYP in a wide time range from 3.16 μs to 300 ms. By the analysis of both kinetics and structures of the intermediates, the structural progression of the protein in the solution phase is vividly visualized. We identify four structurally distinct intermediates and their associated five time constants and reconstructed the molecular shapes of the four intermediates from time-independent, species-associated difference scattering curves. The reconstructed structures of the intermediates show the large conformational changes such as the protrusion of N-terminus, which is restricted in the crystalline phase due to the crystal contact and thus could not be clearly observed by X-ray crystallography. The protrusion of the N-terminus and the protein volume gradually increase with the progress of the photocycle and becomes maximal in the final intermediate, which is proposed to be the signaling state. The data not only reveal that a common kinetic mechanism is applicable to both the crystalline and the solution phases, but also provide direct evidence for how the sample environment influences structural dynamics and the reaction rates of the PYP photocycle.
Journal of the American Chemical Society 02/2012; 134(6):3145-53. · 9.91 Impact Factor
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Tae Wu Kim†,
Jae Hyuk Lee†,
Jungkweon Choi†, Kyung Hwan Kim†,
Luuk J. van Wilderen‡,
Laurent Guerin§,
Youngmin Kim†,
Yang Ouk Jung†,
Cheolhee Yang†,
Jeongho Kim†,
Michael Wulff§,
Jasper J. van Thor*‡,
Hyotcherl Ihee*†
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[hide abstract]
ABSTRACT: Photoreceptor proteins play crucial roles in receiving light stimuli that give rise to the responses required for biological function. However, structural characterization of conformational transition of the photoreceptors has been elusive in their native aqueous environment, even for a prototype photoreceptor, photoactive yellow protein (PYP). We employ pump–probe X-ray solution scattering to probe the structural changes that occur during the photocycle of PYP in a wide time range from 3.16 μs to 300 ms. By the analysis of both kinetics and structures of the intermediates, the structural progression of the protein in the solution phase is vividly visualized. We identify four structurally distinct intermediates and their associated five time constants and reconstructed the molecular shapes of the four intermediates from time-independent, species-associated difference scattering curves. The reconstructed structures of the intermediates show the large conformational changes such as the protrusion of N-terminus, which is restricted in the crystalline phase due to the crystal contact and thus could not be clearly observed by X-ray crystallography. The protrusion of the N-terminus and the protein volume gradually increase with the progress of the photocycle and becomes maximal in the final intermediate, which is proposed to be the signaling state. The data not only reveal that a common kinetic mechanism is applicable to both the crystalline and the solution phases, but also provide direct evidence for how the sample environment influences structural dynamics and the reaction rates of the PYP photocycle.
Journal of American Chemical Society. 01/2012;
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Synthetic Metals. 01/2011; 161(9-10):833-843.
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Youn Sun Kim,
Suk Young Bae, Kyung Hwan Kim,
Tae Wan Lee,
Jung A Hur,
Mai Ha Hoang,
Min Ju Cho,
Sung-Jin Kim,
Youngmee Kim,
Minsik Kim,
Kwangyeol Lee,
Suk Joong Lee,
Dong Hoon Choi
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ABSTRACT: A new pyrene-cored [small pi]-conjugated molecule has been synthesized through Sonogashira coupling reaction. The single-crystalline microribbon-based FET exhibited the highest mobility of 0.7 cm2 V-1 s-1 (Ion/Ioff > 106). Single-crystalline microribbons were employed to operate in an organic phototransistor (OPT) under very low light intensity (I = 5.6 [small mu ]W cm-2).
Chemical Communications. 01/2011; 47(31):8907-8909.
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Organic Electronics. 01/2011; 12(2):269-278.
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Journal of Polymer Science Part A Polymer Chemistry 11/2010; 49(1):55 - 64. · 3.92 Impact Factor
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ABSTRACT: Herein we present the long-sought quantitative catalyst-substrate association relationships based on experimentally measured quantitative association preferences of diverse metathesis Mo and Ru catalysts (Mo-1, Schrock Mo; Mo-2, Schrock-Hoveyda Mo; Ru-1, Grubbs first generation Ru; Ru-2, Grubbs second generation Ru; Ru-3:, Grubbs-Hoveyda first generation Ru; and Ru-4, Grubbs-Hoveyda second generation Ru) to their substrates (alkenes, alkynes and allenes), determined directly by a general method based on FRET principle. The determined substrate preferences are proved to be dependent on the molecular identity of the catalyst, exhibiting the preference order of alkyne > alkene > allene for Mo-1 and Mo-2, allene > alkene > alkyne for Ru-1 and Ru-3, and alkyne > allene > alkene for Ru-2 and Ru-4. The results enable us to probe metathesis mechanisms by answering issues in metathesis reactions including the controversial reaction initiation in enyne or allenyne metathesis.
Journal of the American Chemical Society 09/2010; 132(34):12027-33. · 9.91 Impact Factor
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ABSTRACT: This paper presents the latest results in the use of soluble materials, such as organic semiconductors (OSCs) and gate-dielectrics, for simplified processing of organic thin film transistors (OTFTs). In this work, the fabrication of a solution-processed OTFT, with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and TIPS-pentacene mixed with poly(4-vinylbiphenyl) (PVBP) as the OSC, and propyleneglycolmonomethyletheracetate (PGMEA) as the gate-dielectric, is described. From electrical measurements, we observed exemplary I-V characteristics for these TFTs. Device performance characteristics have been obtained, including the charge carrier mobility (micro) of 1.47 x 10(-2) cm2Ns, threshold voltage (V(T)) of -11.36 V, current on/off ratio (I(ON/OFF)) of 1.08 x 10(4), sub-threshold swing (SS) of 2.13 V/decade for an OTFT with PVBP blended TIPS-pentacene and micro of 1.39 x 10(-4) cm2/Vs, V(T) of 0.7 V, I(ON/OFF) of 1.64 x 10(3), SS of 4.21 V/decade for an OTFT without polymer binder, individually.
Journal of Nanoscience and Nanotechnology 05/2010; 10(5):3198-202. · 1.56 Impact Factor
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ABSTRACT: Organic-soluble DNAs bearing chalcone moieties were synthesized by using purified natural sodium DNA. In addition to the chalcone-containing DNA homopolymer (CcDNA), a copolymer (CTMADNA-co-CcDNA) was synthesized. They were employed as gate insulators for fabricating organic thin-film transistors. An organic semiconductor (5,5′-(9,10-bis((4-hexylphenyl)ethynyl)anthracene-2,6-yl-diyl)bis(ethyne-2,1-diyl)bis(2-hexylthiophene; HB-ant-THT) was deposited on the photocrosslinked DNA-based gate insulators via a solution process. Interestingly, the resulting TFT devices had extremely high field-effect mobilities, and their corresponding transfer curves indicated low hysteresis. The carrier mobility of the device with HB-ant-THT deposited on the CTMADNA-co-CcDNA gate insulator was the best, i.e., 0.31 cm2 V−1 s−1 (Ion/Ioff = 1.0×104).
Applied Physics Letters 03/2010; 96(10):103307-103307-3. · 3.84 Impact Factor
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ABSTRACT: Ultrafast (ps) time-resolved X-ray scattering was used to study the structural dynamics of Ru(3)(CO)(12) in cyclohexane after photolysis at 260 nm. Two intermediates form after 100 ps at the onset of the reaction: Ru(3)(CO)(10) for the CO loss channel and Ru(3)(CO)(11)(mu-CO) for the metal-metal cleavage channel. In our previous study at 390 nm, by contrast, three intermediates were observed simultaneously at the onset of the reaction that all relax back to Ru(3)(CO)(12) with different lifetimes. The major difference between photolysis at 260 and 390 nm is that in the first case Ru(3)(CO)(10)(mu-CO) is formed by bimolecular recombination of Ru(3)(CO)(10) with a free CO in 50 ns, whereas in the second case it forms directly from Ru(3)(CO)(12) at the onset of the reaction. The differences between the photofragmentation pathways are related to the absorption bands available at the two wavelengths. The extrema in the difference radial distribution functions (RDFs) are unambiguously assigned by decomposing the total signal into contributions from the solutes, the solvent and the solute-solvent cross-terms, and also contributions from each candidate species. The difference RDFs reveal the depletion of Ru-Ru bonds (2.88 A) in the initial Ru(3)(CO)(12) molecule and formation of Ru(3)(CO)(10) as the major photoproduct. The high-resolution X-ray (88 keV) scattering pattern of pure liquid C(6)H(12) indicates that the solvent dynamics at early time delays is due to broadening of the intermolecular interatomic correlations at constant volume, whereas during thermal expansion at longer time delays, it results from shifts in these correlations.
Journal of the American Chemical Society 02/2010; 132(8):2600-7. · 9.91 Impact Factor
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Suk Young Bae,
Ki Hwa Jung,
Mai Ha Hoang, Kyung Hwan Kim,
Tae wan Lee,
Min Ju Cho,
Jung-Il Jin,
Dong Hoon Lee,
Dae Sung Chung,
Chan Eon Park,
Dong Hoon Choi
Synthetic Metals. 01/2010; 160(9-10):1022-1029.
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ABSTRACT: New anthracene-based X-shaped conjugated molecules and for use as highly soluble p-type organic semiconductors were developed and exhibited large field-effect mobilities of 0.04 cm(2) V(-1) s(-1) (I(on)/I(off) = 2.8 x 10(5)) and 0.24 cm(2) V(-1) s(-1) (I(on)/I(off) = 5.4 x 10(6)) for devices of and , respectively.
Chemical Communications 10/2009; · 6.17 Impact Factor
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ABSTRACT: The active channel material of an organic thin film transistor (OTFT), 6,13-bis(tri-isopropylsilylethynyl)pentacene (TIPS pentacene), is a functionalized pentacene designed to enhance both the solubility and solid-state packing of the pentacene. In this work, in order to improve device performance, three types of polymer binders—poly(α-methylstyrene) (PAMS), poly(4-vinylbiphenyl) (PVBP), and poly(triarylamine) (PTAA)—were employed to fabricate OTFT devices with organic soluble TIPS pentacene. These binders improved film formation in a large area uniformly and helped the TIPS pentacene to form a stronger binding between source/drain electrodes onto dielectric layer. Thus, device performance was highly improved due to improvement of interfacial contact and an increase in the charge transfer in the active channel. OTFTs using TIPS pentacene with PAMS, PVBP, and PTAA for field effect mobilities in the saturation regime have 5×10−3, 8×10−3, and 2.7×10−2 cm2/V s, respectively.
Applied Physics Letters 01/2009; 94(1):013506-013506-3. · 3.84 Impact Factor
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Journal of the American Chemical Society 01/2009; 130(49):16506-7. · 9.91 Impact Factor
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ABSTRACT: We present the latest results of the use of soluble materials such as organic semiconductors (OSCs) or gate-dielectrics for simplified processing of organic thin-film transistors (OTFTs). In this paper, we described our fabrication of a solution-processed OTFT with 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) as the OSC and siloxane-based spin-on glass (SOG) as the inorganic gate-dielectric. Also, synthesized TIPS-pentacene and SOG were examined for use as the OSC and gate-dielectric in an OTFT. From electrical measurements, we obtained device performance characteristics such as charge carrier mobility, threshold voltage, current ON/OFF ratio, and subthreshold swing, which were 6.48 times 10<sup>-3</sup> cm<sup>2</sup>/V ldr s, -13 V, ~100, and 1.83 V/dec, respectively.
IEEE Transactions on Electron Devices 03/2008; · 2.32 Impact Factor
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Angewandte Chemie International Edition 02/2008; 47(6):1047-50. · 13.45 Impact Factor
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ABSTRACT: New benzothieno[3,2-b]benzothiophene (BTBT)-based soluble semiconducting molecules have been synthesized through Horner-Emmons coupling reactions using 5-alkylthiophene-2-carbaldehyde and BTBT-diethylphosphonate. The only difference between the two molecules is the length of alkyl chains as a substituent. The molecules are intrinsically thermotropic liquid crystalline (LC) and exhibit good solubility in common organic solvents. The semiconducting properties of the two LC molecules were evaluated in organic thin film transistors (OTFTs). After annealing the samples at the temperature at which liquid crystallinity appears, the TFT device performance improved significantly. The two conjugated molecules 4 and 5 exhibited fairly high charge carrier mobilities of 0.020 cm2/(Vs) (Vth = −14.5 V, ION/OFF = 1.42 × 105) and 0.023 cm2/(Vs) (Vth = −2.0 V, ION/OFF = 1.20 × 106), respectively.
Organic Electronics 11(9):1584-1593. · 4.05 Impact Factor
