Small-signal characteristics of fully-printed high-current flexible all-polymer three-layer-dielectric transistors (original) (raw)
Related papers
Flexible high capacitance nanocomposite gate insulator for printed organic field-effect transistors
Thin Solid Films, 2010
Ceramic-polymer nanocomposite dielectric consisting of an epoxy solution with Propylene Glycol Methyl Ether Acetate as the solvent and Barium Titanate nanoparticles with capacitance in excess of 60 pF/mm 2 was developed and utilized as the gate insulator for organic field effect transistors (OFETs). The high relative permittivity (κ = 35), bimodal nanocomposite utilized had two different filler particle sizes 200 nm and 1000 nm diameter particles. Bottom gate organic filed effect transistors were demonstrated using a commercially available printing technology for material deposition. A metal coated plastic film was used as the flexible gate substrate. Solution processable, p-type arylamine based amorphous organic semiconductor was utilized as the active layer. Fabricated OFETs with the solution processed nanocomposite dielectric had a high fieldinduced current and a low threshold voltage; these results suggest that the low operating voltage was due to the high capacitance gate insulator. In this paper, we review the characteristics of the nanocomposite dielectric material and discuss the processing and performance of the printed organic devices.
IEEE Transactions on Circuits and Systems I: Regular Papers, 2016
In this paper, a printed audio amplifier, which is a new application for organic electronics, is suggested. The amplifier consists of several fully-printed bendable components including: a loudspeaker, organic field effect transistors (OFETs), capacitors, and resistors. All components are fabricated on polyethylene terephthalate (PET) substrate by means of high-throughput printing techniques. A complete self-biased circuit is reported consisting of large multi-finger OFETs with channel length of 20 μm and total width of 0.475 meter. The amplifier provides a peak voltage gain of 18 dB at 400 Hz, can reproduce sound pressure level of 36-60 dBA over 700 Hz to 12.5 kHz at one meter distance, and has a unity-gain-bandwidth of 17.7 kHz/5.2 kHz when driving 0 nF/∼39 nF load at V DD = 80 V, respectively. The impact of bias-stress effects on the amplifier performance is measured to be ∼3 dBA sound loss after 5 hours of continuous operation. The whole circuit is packaged and laminated on a separate PET sheet. In addition, the intrinsic electrical impedance of the printed PVDF-TrFE piezoelectric polymer used in the loudspeaker is characterized, and is modeled by a complex dielectric constant.
Voltage and Thermally Driven Roll-to-Roll Organic Printed Transistor Made in Ambient Air Conditions
2017
Conditions DTU Orbit (20/10/2019) Voltage and Thermally Driven Roll-to-Roll Organic Printed Transistor Made in Ambient Air Conditions Resume: Organic thin film transistors offer great potential for use in flexible electronics. Much of this potential lies in the solution processability of the organic polymers enabling both roll coating and printing on flexible substrates and thus greatly reducing the material and fabrication costs. We present flexible organic power transistors prepared by fast (20 m min−1) roll-to-roll flexographic printing of the drain and source electrode structures, with an interspace below 50 um, directly on polyester foil[1]. The devices have top gate architecture and were completed by slotdie coating of the organic semiconductor poly3hexylthiophene and the dielectric material polyvinylphenol before the gate was applied by screen printing. All the processing was realized in ambient air on a PET flexible substrate. We explore the footprint and the practically acc...
Organic Electronics, 2016
Flexible organic field-effect transistors (OFETs) with TIPS-pentacene: polystyrene (PS) blend are demonstrated to exhibit enhanced mobility and significantly improved electrical stability compared to neat TIPS-pentacene on poly(4-vinylphenol) (PVP) dielectric (bi-layer OFETs), along with high mechanical stability. Due to merit of high quality dielectric-semiconductor interface, pristine TIPSpentacene: PS blend OFETs exhibited maximum mobility of 0.93 cm 2 V À1 s À1 with average of 0.44(±0.25) cm 2 V À1 s À1 compared to 0.14(±0.10) cm 2 V À1 s À1 for bi-layer OFETs with high current on-off ratios on the order 10 5 for both. Both types of devices exhibited high electrical stability upon bending with increasing magnitude of strain or its duration up to 5 days. However, significant differences in electrical stability of devices were observed upon applying constant bias-stress for 40 min to 1 h. Pristine blend devices exhibited outstanding electrical stability with very low drain current decay of <5% compared to~30% for bi-layer devices. Even upon bias-stress after 5 days of bending, the drain current decay levels were only changed to <10% and~50% for blend and bi-layer devices respectively.
Applied Physics Letters, 2009
We demonstrate low-voltage, solution-processed organic transistors on rough plastic substrates with a carrier mobility over 0.2 cm2/V s, a turn-on voltage of near 0 V, and a record low subthreshold slope of ∼80 mV/decade in ambient conditions. These exceptional characteristics are attributed to (1) a device stacking architecture with a conducting polymeric gate and a double layered dielectric composed of low-temperature cross-linked poly(4-vinylphenol), (2) a low interface trap density achieved by modifying the dielectric surface with a phenyl-terminated self-assembled monolayer from 4-phenylbutyltrichlorosilane, and (3) controlled crystallization of a small-molecule organic semiconductor film with favorable charge transport microstructure and a low bulk trap density as deposited by an optimized solution-shearing process. The device performance under different operating voltages was also examined and discussed.
… Applied Materials & …, 2012
An organic−organic blend thin film has been synthesized through the solution deposition of a triblock copolymer (Pluronic P123, EO 20 −PO 70 −EO 20 ) and polystyrene (PS), which is called P123−PS for the blend film whose precursor solution was obtained with organic additives. In addition to having excellent insulating properties, these materials have satisfied other stringent requirements for an optimal flexible device: lowtemperature fabrication, nontoxic, surface free of pinhole defect, compatibility with organic semiconductors, and mechanical flexibility. Atomic force microscope measurements revealed that the optimized P123−PS blend film was uniform, crack-free, and highly resistant to moisture absorption on polyimide (PI) substrate. The film was well-adhered to the flexible Au/Cr/PI substrate for device application as a stable insulator, which was likely due to the strong molecular assembly that includes both hydrophilic and hydrophobic effects from the high molecular weights. The contact angle measurements for the P123−PS surface indicated that the system had a good hydrophobic surface with a total surface free energy of approximately 19.6 mJ m −2 . The dielectric properties of P123−PS were characterized in a cross-linked metal− insulator−metal structured device on the PI substrate by leakage current, capacitance, and dielectric constant measurements. The P123−PS film showed an average low leakage current density value of approximately 10 −10 A cm −2 at 5−10 MV cm −1 and large capacitance of 88.2 nF cm −2 at 1 MHz, and the calculated dielectric constant was 2.7. In addition, we demonstrated an organic thin-film transistor (OTFT) device on a flexible PI substrate using the P123−PS as the gate dielectric layer and pentacene as the channel layer. The OTFT showed good saturation mobility (0.16 cm 2 V −1 s −1 ) and an on-to-off current ratio of 5 × 10 5 . The OTFT should operate under bending conditions; therefore flexibility tests for two types of bending modes (tensile and compressive) were also performed successfully.
Pentacene organic field-effect transistors (OFETs) were fabricated by inserting a thin metallic oxide material MoO 3 between pentacene and gold (Au) electrodes as an interlayer. Comparing with the corresponding single layer OFETs without any interlayer, theses OFETs with a thin MoO 3 interlayer showed an obvious enhancement of hole mobility and slightly decrease of threshold voltage. The improvement of performance was investigated by interfacial energy level of the organic/metal interface, which showed that the MoO 3 interlayer could significantly reduce the injection barrier between Au and pentacene. Moreover, the reduction of the injection barrier leads to a decrease of contact resistance at organic/metal interface, which improve the performance of the devices.
Applied Physics Letters, 2008
Transparent organic field-effect transistors based on pentacene were fabricated on indium tin oxide (ITO)-coated glass using ITO as the gate electrode, Al2O3 grown by atomic layer deposition as the gate insulator, and an inkjet-printed conducting polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulphonate) as the source and drain electrodes. The transistors combine an overall high transmittance (84% in the channel and 78% through source/drain electrodes) in the visible region, a field-effect mobility value of 0.3cm2∕Vs, a threshold voltage of −0.2V, a subthreshold slope of 0.9V/decade, and an on/off current ratio of 105.