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1.
A series of derivatives based on annelated β-oligothiophenes were synthesized and characterized as active layer in organic field-effect transistors (OFETs). Highest field-effect mobility of 0.52 V?1 s?1 for 2,5-dibiphenyl-dithieno[2,3-b:3′,2′-d]thiophene (DBP-DTT), 2.2 cm2 V?1 s?1 for 2,5-distyryl-dithieno[2,3-b:3′,2′-d]thiophene (DEP-DTT), and 0.16 cm2 V?1 s?1 for 1,4-di[2-dithieno[2,3-b:3′,2′-d] thiophen-2-yl-vinyl]benzene (DDTT-EP) were obtained, while 2,5-diphenyl-dithieno [2,3-b:3′,2′-d]thiophene (DP-DTT) presents no field-effect behaviors. Their thermal, optical and electrochemical properties, topographical and X-ray diffraction patterns of films, and the single crystal structures were also investigated. With the end-capping groups changing in these materials, the intermolecular interactions could transform from S–S in DP-DTT to S–C in DBP-DTT, to S–π in DEP-DTT, and to the coexisting of S–S and S–π in DDTT-EP. According to the device performances and the results of transfer integral calculations, it was revealed that S–π intermolecular interaction benefits not only improving the mobility but also reducing the threshold voltage (VT), while S–S intermolecular interaction is not favorable for promoting the mobility. 相似文献
2.
《Organic Electronics》2014,15(6):1184-1188
Single-crystalline organic transistors of 3,11-didecyl-dinaphtho[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene (C10-DNBDT-NW) and 2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (C10-DNTT) were fabricated by solution processes on top of the patterned hybrid ultrathin gate dielectrics consisting of 3.6 nm-thick aluminum oxide and self-assembled monolayers (SAMs). Due to the excellent crystallinity of the channel films, bottom-gate and top-contact field-effect transistors exhibited the average field-effect mobility of 3.7 cm2/V s and 4.3 cm2/V s for C10-DNBDT-NW and C10-DNTT, respectively. These are the first successful devices of solution-processed single-crystalline transistors on ultrathin gate dielectrics with the mobility above 1 cm2/V s, opening the way to develop low-power-consumption and high-performance printed circuits. 相似文献
3.
Electroless-plated gold and platinum films are used as source and drain electrodes in high-performance solution-processed organic field-effect transistors (OFETs), representing a promising large-area, near-room-temperature and vacuum-free technique to form low-resistance metal-to-semiconductor interfaces in ambient atmosphere. Developing non-displacement conditions using a Pt-colloidal catalyst for soft electroless plating, the electrodes are deposited on crystallized thin films of 2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (C10-DNTT) without significant damage to the semiconductor material. The top-contact OFETs show remarkable performance, with a mobility of 6.0 cm2 V?1 s?1. The method represents a practical fabrication technique to mass-produce circuitry arrays of nearly best-performing OFETs for the printed electronics industry. 相似文献
4.
Jing Zhang Hongfei Zhu Lei Zhang Chong-an Di Wei Xu Wenping Hu Yunqi Liu Daoben Zhu 《Organic Electronics》2012,13(5):733-736
A solution-based transparent polymer was investigated as the gate dielectric for organic field-effect transistors (OFETs). Organic thin films (400 nm) are readily fabricated by spin-coating a polyhydrazide solution under ambient conditions on the ITO substrates, followed by annealing at a low temperature (120 °C). The smooth transparent dielectrics exhibited excellent insulating properties with very low leakage current densities of ~10?8 A/cm2. High performance OFETs with evaporated pentacene as organic semiconductor function at a low operate voltage (?15 V). The mobility could reach as high as 0.7 cm2/Vs and on/off current ratio up to 104. Solution-processed TIPS-pentacene OFETs also work well with this polymer dielectric. 相似文献
5.
We have demonstrated top-gate polymer field-effect transistors (FETs) with ultra-thin (30–50 nm), room-temperature crosslinkable polymer gate dielectrics based on blending an insulating base polymer such as poly(methyl methacrylate) with an organosilane crosslinking agent, 1,6-bis(trichlorosilyl)hexane. The top-gate polymer transistors with thin gate dielectrics were operated at gate voltages less than ?8 V with a relatively high dielectric breakdown strength (>3 MV/cm) and a low leakage current (10–100 nA/mm2 at 2 MV/cm). The yield of thin gate dielectrics in top-gate polymer FETs is correlated with the roughness of underlying semiconducting polymer film. High mobilities of 0.1–0.2 cm2/V s and on and off state current ratios of 104 were achieved with the high performance semiconducting polymer, poly(2,5-bis(3-alkylthiophen-2yl)thieno[3,2-b]thiophene. 相似文献
6.
《Organic Electronics》2008,9(3):317-322
With the aim of enhancing the field-effect mobility of poly(3-hexylthiophene) (P3HT) field-effect transistors (FETs), we added functionalized multiwalled carbon nanotubes (CNTs) to the P3HT solution prior to film formation. The nanotubes were found to be homogeneously dispersed in the P3HT films because of their functional groups. We found that at the appropriate CNT concentration (up to 10 wt% CNT), the P3HT FETs have a high field-effect mobility of 0.04 cm2 V−1 s−1, which is an improvement by a factor of more than 10. This remarkable increase in the field-effect mobility over that of the pristine P3HT film is due to the high conductivity of the CNTs which act as conducting bridges between the crystalline regions of the P3HT film, and the reduction in the hole-injection barrier due to the low work function of CNTs, which results in more efficient carrier injection. 相似文献
7.
High-mobility organic single-crystal field-effect transistors of 3,11-didecyldinaphtho[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]-dithiophene (C10-DNBDT) operating at low driving voltage are fabricated by an all-solution process. A field-effect mobility as high as 6.9 cm2/V s is achieved at a driving voltage below 5 V, a voltage as low as in battery-operated devices, for example. A low density of trap states is realized at the surface of the solution-processed organic single-crystal films, so that the typical subthreshold swing is less than 0.4 V/decade even on a reasonably thick amorphous polymer gate dielectrics with reliable insulation. The high carrier mobility and low interface trap density at the surface of the C10-DNBDT crystals are both responsible for the development of the high-performance all-solution processed transistors. 相似文献
8.
Control of the threshold voltage and the subthreshold swing is critical for low voltage transistor operation. In this contribution, organic field-effect transistors (OFETs) operating at 1 V using ultra-thin (∼4 nm), self-assembled monolayer (SAM) modified aluminium oxide layers as the gate dielectric are demonstrated. A solution-processed donor–acceptor semiconducting polymer poly(3,6-di(2-thien-5-yl)-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione)thieno[3,2-b]thiophene) (PDPP2TTT) is used as the active layer. It is shown that the threshold voltage of the fabricated transistors can be simply tuned by carefully controlling the composition of the applied SAM. The optimised OFETs display threshold voltages around 0 V, low subthreshold slopes (150 ± 5 mV/dec), operate with negligible hysteresis and show average saturated field-effect mobilities in excess of 0.1 cm2/V s at 1 V. 相似文献
9.
The structures, optical properties, thin-film and single-crystal field-effect transistor performance of three thiophene-based hybrid materials, 5-(9-butyl-3-carbazolyl)terthiophene (BCTT), 2,5-bis(9-butyl-3-carbazolyl)thiophene (BBCT) and 2-(9-butyl-3-carbazolyl)-5-(2-dibenzothienyl)thiophene (BCDT), are reported. The structural modifications at one side of thiophene have significant effects on the intermolecular interaction, morphology and carrier-transport properties. The adjacent molecules in the solid state of BCTT adopt H aggregation, while compounds BBCT and BCDT both exhibit the formation of J aggregation. In BCTT, the crystal structure features a herringbone motif. The hole mobility for the single-crystal field-effect transistor based on BCTT reaches 0.094 cm2 V?1 s?1, which is much higher than those of BBCT and BCDT. This study reveals that the enhanced rigidity in the molecules of BBCT and BCDT is not favorable to carrier transport. 相似文献
10.
Room-temperature exposure of spin-coated poly(3-hexylthiophene) (P3HT) films to ortho-dichlorobenzene vapor increases the field-effect mobility of the P3HT organic thin-film transistors (OTFTs). The mobility increases moderately with unsaturated vapor exposure, owing to increased crystallinity of the P3HT films; on the other hand, the mobility increases abruptly with saturated vapor exposure, to 0.11 cm2/V s. The saturated vapor exposure causes the P3HT films to reflow, leaving in the active area approximately 2–3 P3HT monolayers whose molecular ordering is enhanced by the flow-generated shear against the gate dielectric. Although the reflowed OTFTs degrade in air much faster than do the non-reflowed OTFTs due to the susceptibility of the ultra-thin reflowed films, they become highly stable when encapsulated, obtaining a lifetime of more than 3000 h. 相似文献
11.
《Organic Electronics》2008,9(5):753-756
High-mobility rubrene single-crystal field-effect transistors are built on highly water- and oil-repellent fluoropolymer gate insulators. Roughness is introduced at the surface once to provide good adhesion to metal films and photoresist polymers for stable electrodes. Before constructing interfaces to crystals, smoothness of the fluoropolymer surface is recovered by annealing at a moderate temperature to maximize carrier mobility. Mobility values estimated in the saturation region reproducibly exceeded 15 cm2/V s for all the 10 devices, reaching 30 cm2/V s for the best two devices. The results demonstrate that the water-repellency and smoothness of the dielectric polymers are favorable for the excellent transistor performance. 相似文献
12.
Kipyo Hong Sooji Nam Chanwoo Yang Se Hyun Kim Dae Sung Chung Won Min Yun Chan Eon Park 《Organic Electronics》2009,10(2):363-367
Multiwalled carbon nanotubes (MWNTs) were solubilized in water by wrapping them noncovalently with poly(4-styrene sulfonate) (PSS). The PSS-wrapped MWNTs exhibited a high conductivity (2.0 × 102 S/cm) when compared to other solution-processed electrodes. Ultraviolet photoelectron spectroscopy results show the PSS-wrapped nanotubes have a work function of 4.83 eV, which is 0.36 eV higher than that of untreated MWNTs. We fabricated triisopropylsilylethynyl pentacene field-effect transistors (FETs) using the PSS-wrapped MWNTs as source/drain electrodes and found that the field-effect mobility of the thus obtained devices was 0.043 cm2 V?1 s?2. This mobility is four times higher than that of similar FETs containing gold electrodes (0.011 cm2 V?1 s?2). 相似文献
13.
Ute Zschieschang Robert Hofmockel Reinhold Rödel Ulrike Kraft Myeong Jin Kang Kazuo Takimiya Tarek Zaki Florian Letzkus Jörg Butschke Harald Richter Joachim N. Burghartz Hagen Klauk 《Organic Electronics》2013,14(6):1516-1520
Bottom-gate, top-contact (inverted staggered) organic thin-film transistors with a channel length of 1 μm have been fabricated on flexible plastic substrates using the vacuum-deposited small-molecule semiconductor 2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (C10-DNTT). The transistors have an effective field-effect mobility of 1.2 cm2/V s, an on/off ratio of 107, a width-normalized transconductance of 1.2 S/m (with a standard deviation of 6%), and a signal propagation delay (measured in 11-stage ring oscillators) of 420 ns per stage at a supply voltage of 3 V. To our knowledge, this is the first time that megahertz operation has been achieved in flexible organic transistors at supply voltages of less than 10 V. 相似文献
14.
Xinping Liu Ji Zhang Peng Tang Gui Yu Zhiyong Zhang Huajie Chen Ya Chen Bin Zhao Songting Tan Ping Shen 《Organic Electronics》2012,13(9):1671-1679
A new donor–acceptor (D?A) copolymer (PIPY–DTBTA) containing 6,12-dihydro-diindeno[1,2-b;1′,2′-e]pyrazine donor and benzotriazole acceptor was synthesized and characterized for multifunctional applications in organic field-effect transistors (OFETs), polymer solar cells (PSCs) and polymer light-emitting diodes (PLEDs). The polymer exhibits high molecular weights, excellent film-forming ability, a deep HOMO energy level, and good solution processability. Solution-processed thin film OFETs based on this polymer revealed good p-type characteristic with a high hole mobility up to 0.0521 cm2 V?1 s?1. Bulk-heterojunction PSCs comprising this polymer and PC61BM gave a power conversion efficiency (PCE) of 0.77%. The single-layer PLEDs based on PIPY–DTBTA emitted a yellow–red light with a maximum brightness of 385 cd m?2 at the turn-on voltage of 6 V. 相似文献
15.
《Organic Electronics》2008,9(1):143-148
We report on the preparation of large area coverage of well-oriented films of dithiophene-tetrathiafulvalene (DT-TTF) from solution by using the zone casting technique. The X-ray analysis shows that the molecules are highly ordered in the films with the stacking direction parallel to the substrate. We further demonstrate that it is possible to prepare organic field-effect transistors (OFETs) employing these films. The devices reveal a remarkable OFET mobility with a maximum value of 0.17 cm2/V s. The fact that the films are prepared from solution makes these devices eminently suitable for low-cost electronics. 相似文献
16.
Here, we report hybrid organic/inorganic ferroelectric memory with multilevel information storage using transparent p-type SnO semiconductor and ferroelectric P(VDF-TrFE) polymer. The dual gate devices include a top ferroelectric field-effect transistor (FeFET) and a bottom thin-film transistor (TFT). The devices are all fabricated at low temperatures (∼200 °C), and demonstrate excellent performance with high hole mobility of 2.7 cm2 V−1 s−1, large memory window of ∼18 V, and a low sub-threshold swing ∼−4 V dec−1. The channel conductance of the bottom-TFT and the top-FeFET can be controlled independently by the bottom and top gates, respectively. The results demonstrate multilevel nonvolatile information storage using ferroelectric memory devices with good retention characteristics. 相似文献
17.
Oriented organic field-effect transistor (OFET) stripe arrays on hydrophobic substrates were fabricated by fast dip-coating technique. The addressable growth was achieved by decreasing surface energy of the channel areas with respect to the electrodes via hydrophobic treatment. The higher surface energy of the electrodes allows solution to adhere and then organic semiconductors nucleate and bridge the channels after evaporation of the solvent. Area-selective behaviour can be controlled by adjusting surface property of transistor channel, geometry features of the gold electrodes, pulling speed and evaporation atmosphere. The mechanism behind is the competition between receding of the solution and evaporating of the solvent that generate the organic semiconductor films on the substrate. The patterned bottom-contact transistor arrays exhibit carrier mobility of 2.0 × 10−3 cm2 V−1 s−1, while no field-effect characteristics can be detected for bottom-contact arrays without hydrophobic treatment. Such reliable, fast and solution-based patterned OFET arrays are highly desirable for large-scale and low-cost production. 相似文献
18.
Fluorine doped tin oxide (FTO) films were fabricated on a glass substrate by a green sol–gel dip-coating process. Non-toxic SnF2 was used as fluorine source to replace toxic HF or NH4F. Effect of SnF2 content, 0–10 mol%, on structure, electrical resistivity, and optical transmittance of the films were investigated using X-ray diffraction, Hall effect measurements, and UV–vis spectra. Structural analysis revealed that the films are polycrystalline with a tetragonal crystal structure. Grain size varies from 43 to 21 nm with increasing fluorine concentration, which in fact critically impacts resultant electrical and optical properties. The 500 °C-annealed FTO film containing 6 mol% SnF2 shows the lowest electrical resistivity 7.0×10−4 Ω cm, carrier concentration 1.1×1021 cm−3, Hall mobility 8.1 cm2V−1 s−1, optical transmittance 90.1% and optical band-gap 3.91 eV. The 6 mol% SnF2 added film has the highest figure of merit 2.43×10−2 Ω−1 which is four times higher than that of un-doped FTO films. Because of the promising electrical and optical properties, F-doped thin films prepared by this green process are well-suited for use in all aspects of transparent conducting oxide. 相似文献
19.
《Organic Electronics》2014,15(8):1799-1804
Copper phthalocyanine (CuPc)-based thin film transistors were fabricated using CuPc films grown under different deposition pressure (Pdep) (ranging from 1.8 × 10−4 Pa to 1.0 × 10−1 Pa). The transistor performance highly depended on Pdep. A field-effect mobility of 2.1 × 10−2 cm2/(V s) was achieved under 1.0 × 10−1 Pa. Detailed investigations revealed that Pdep modulates the molecular packing and orientation of the organic films grown on a SiO2/Si substrate and influences the charge transport. Furthermore, from a device physics point of view, contact resistance of the fabricated transistors decreased when Pdep increased, which was beneficial in reducing energy consumption. 相似文献
20.
Mai Ha Hoang Min Ju Cho Dae Cheol Kim Kyung Hwan Kim Ji Won Shin Mi Yeon Cho Jin-soo Joo Dong Hoon Choi 《Organic Electronics》2009,10(4):607-617
A number of semiconducting organic molecules capable of wet processing exhibit high carrier mobility and current modulation. In this work, we synthesized photopatternable π-conjugated star-shaped molecules and characterized their physical properties. The solubility of the synthesized molecules is very good for solution processing. The synthesized organic semiconducting multi-branched molecules are capable of photopatterning by virtue of photopolymerization of the reactive pentadienyl end groups. The transistor devices using these molecules provided a field-effect mobility of 1.3(±0.2) × 10?3–3.7(±0.5) × 10?3 cm2 V?1 s?1 as well as a high current on/off ratio (Ion/off > 103) and a low threshold voltage. In the case of the photoreactive star-shaped conjugated molecule HP2P, it was found that field-effect mobility was maintained even after the photocrosslinking process. This result can be used in the design of photopatternable semiconductor molecules for thin-film transistor electronic applications. 相似文献