• Polymer(Korea)
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• v.38 no.2
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• pp.188-192
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• 2014

In this work, it is possible to simply improve the molecular ordering of a conjugated polymer thin film by dipping into poor solvent. The structural order, optical, and electrical properties of poly(3-hexylthiophene) (P3HT) films were profoundly influenced by dipping time and solubility of solvent. Especially the dipping time in methylene chloride was controlled to efficiently improve the molecular ordering of the P3HT. The correlation between the structural order and the electrical properties was used to optimize the dipping time in the appropriate solvent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.312-315
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• 2001

Recently organic electroluminescent devices have been intensively investigated for using in full-color flat-panel display. Since the quantum efficiency of electrophosphorescent device decrease rapidly as the luminance increase, it is desirable to operate the electrophosphorescent display with active matrix rather than passive matrix. Here we report the study of driving electrophosphorescent diode with all organic thin film transistor(OTFT). The structure of electrophosphorescent diode is ITO/TPD/BCP:Ir(ppy)$_3$/BCP/Alq$_3$/Li:Al/Al. In OTFT. polymer is used as an insulator and pentacene as an active layer. Detailed performance of the integrated device will be discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.312-315
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• 2001

Recently organic electroluminescent devices have been intensively investigated for using in full-color flat-panel display. Since the quantum efficiency of electrophosphorescent device decrease rapidly as the luminance increase, it is desirable to operate the electrophosphorescent display with active matrix rather than passive matrix. Here we report the study of driving electrophosphorescent diode with all organic thin film transistor(OTFT). The structure of electrophosphorescent diode is ITO/TPD/BCP:Ir(ppy)$_3$/BCP/Alq$_3$/Li:Al/Al. In OTFT, Polymer is used as an insulator and pentacene as an active layer. Detailed performance of the integrated device will be discussed.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.17.2-17.2
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• 2010

Printed electronics is an emerging technology to realize various microelectronic devices via a cost-effective method. Here we demonstrated a high performance of p-channel and n-channel top-gate/bottom contact polymer field-effect transistors (FETs), and applications to elementary organic complementary inverter and ring oscillator circuits by inkjet processing. We could obtained high field-effect mobility more than $0.4\;cm^2/Vs$ for both of p-channel and n-channel FETs, and successfully measured inkjet-printed polymer inverters. The performance of devices highly depends on the selection of dielectrics, printing condition and device architecture. Optimized CMOS ring oscillators with p-type and n-type polymer transistors showed as high as 50 kHz operation frequency. This research was financially supported by development of next generation RFID technology for item level applications (2008-F052-01) funded by the ministry of knowledge economy (MKE).

• Macromolecular Research
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• v.17 no.6
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• pp.436-440
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• 2009

We improved the performance of pentacene-based thin film transistors by changing the curing environment of poly(4-vinylphenol) (PVP) gate dielectrics, while keeping the dielectric constant the same. The field-effect mobility of the pentacene TFTs constructed using the vacuum cured PVP was higher than that of the device based on the Ar flow cured gate dielectric, possibly due to the higher crystalline perfection of the pentacene films. The present results demonstrated that the curing conditions used can markedly affect the surface energy of polymer gate dielectrics, thereby affecting the field-effect mobility of TFTs based on those dielectrics.

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.165-168
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• 2015

We demonstrated low-voltage organic thin-film transistors (OTFTs) with bilayer insulators, high-k polymer and low temperature crosslinkable polymer, on a flexible plastic substrate. Poly (vinylidene fluoridetrifluoroethylene) (P(VDF-TrFE)) and poly (2-vinylnaphthalene) are used for high-k polymer gate insulator and low temperature crosslinkable polymer insulators, respectively. The mobility of flexible OTFTs is $0.17cm^2/Vs$ at gate voltages -5 V after bending operation.

• Journal of Integrative Natural Science
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• v.4 no.4
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• pp.294-297
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• 2011

Quality of PEDOT electrode thin film vapor phase-polymerized on 3-aminopropyltriethoxysilane (APS) self-assembled monolayer (SAM) is very crucial for making an ohmic contact between electrode and semiconductor layer of an organic transistor. In order to improve the quality of PEDOT film, the quality of APS-SAM laying underneath the film must be in the best condition. In this study, in order to improve the quality of APS-SAM, the monolayer was self-assembled on $SiO_2$ surface by a dip-coating method under strictly controlled relative humidity (< 18%RH). The quality of APS-SAM and PEDOT thin film were investigated with a contact angle analyzer, AFM, FE-SEM, and four-point probe. The investigation showed that a PEDOT film grown on the humidity-controlled SAM is very smooth and compact (sheet resistivity = 20.2 Ohm/sq) while a film grown under the uncontrolled condition is nearly amorphous and contains quite many pores (sheet resistivity = 200 Ohm/sq). Therefore, this study clearly proves that a highly improved quality of APSSAM can offer a highly conductive PEDOT electrode thin film on it.

• Journal of Integrative Natural Science
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• v.2 no.1
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• pp.13-17
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• 2009

A newly developed OTFT manufacturing process using the combination of self-assembly techniques and vapor phase polymerization method revealed that a thick $SiO_2$ dielectric layer (100~200 nm) is not well compatible with conducting polymer electrode, thereby resulting in still recognizable contact resistance, unstable $V_{th}$ and leaking off current. A couple of very recent studies showed that this issue may be solved by replacing such inorganic dielectric with a self-assembled monolayer or multilayer (organic) dielectric. Therefore, this short review introduces recent trends in the development of high performance thin film transistor consisting of both organic semiconductor and SAM dielectric.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.151-154
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• 2007

We demonstrate a novel selective patterning process of a semiconducting polymer for channel regions to fabricate an array of organic thin-film transistors (OTFTs). This process is applicable for various organic films over large area. A reflective liquid crystal display based on the OTFT array was produced using the selective patterning through a wettability control.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1046-1048
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• 2004

Performances of organic thin film transistors (OTFTs) can be detrimentally affected by the state of the gate dielectric. Because of the bad stability of polymers, OTFTs with polymer gate dielectrics often provide abnormal characteristics. In this study, we report the condensation effect of the polymer gate dielectric layer. For the observations of the effect of the condensation, the spin-coated polymer layers with various deposition conditions were fabricated and left under low vacuum condition for several days. It is observed that the thickness of polymer layer and the electrical characteristic of OTFTs vary with the condensation time.