• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.629-632
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• 2008

Printed organic thin-film transistors (OTFTs) were used in the fabrication of a screen- printed gate, source and drain electrodes on flexible plastic substrates using silver pastes, a coated polyvinylphenol dielectrics, and jetted bis(triisopropyl-silylethynyl) pentacene (TIPS-pentacene) organic semiconductor. The OTFTs printed using screen printing and soluble processes made it was possible to fabricate a printed OTFT with a channel length as small as $13\;{\mu}m$ on plastic substrates; this was not possible using previous traditional printing techniques.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.917-919
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• 2009

Effects of nano-silver contents(15~50wt%) on screen printed-etched gate electrodes and electrical characteristics of OTFTs were investigated. As Ag contents increased, the screen-printed film was transferred exactly without spreading and obtained the densely-packed layer with a stable and excellent conductivity but, its thickness was increased and surface became rougher. It was found that the leakage current of MIM devices and off-state currents of OTFTs became larger due to poor step coverage of PVP dielectric layer on the thick and rough gate electrodes for nano-Ag inks with Ag contents more than 30wt%.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.896-898
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• 2009

The printed electrodes of organic thin-film transistors (OTFTs) were fabricated by screen printing using nanoparticle silver pastes. The screen printed OTFT corresponds to channel lengths between 7.6 to 82.6 ${\mu}m$ (designed L=10 to 80 ${\mu}m$) on the $150{\times}150mm^2$ paper. The channel length deviations for 40 to 80 ${\mu}m$ patterns were less than 5 %. However, the channel lengths for 10 to 30 ${\mu}m$ patterns were increased by 20 %. The screen printed bis(triisopropyl-silylethynyl) pentacene (TIPS-pentacene) OTFTs obtained had a field-effect mobility as large as 0.08 (${\pm}0.02$) $cm^2$/Vs, an on/off current ratio of $10^5$ and a subthreshold slope of 1.95 V/decade.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1305-1307
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• 2007

We show that the electrical properties of organic thinfilm transistors(OTFTs) can be enhanced by controlling the morphology of interface between screen printed electrodes and gate dielectrics. Modified surface of the insulator layer($SiO_2$) affect on the interface energy of electrode on $SiO_2$ layer. Contact angle measurement and FT-IR spectrum shows that the interface is properly modified. OTFTs device with high efficiency has been realized through modification of interface layer.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1312-1314
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• 2007

The effect of gate insulator surface treatment on electrical characteristics of bottom contact (BC) and suspended source/drain (SSD) organic thinfilm transistors (OTFTs) was studied. Triisopropylsilylethynyl pentacene was used as an active material and was printed by ink-jet printing method. In case of the BC OTFTs, threshold voltage was shifted from positive to near zero, and the fieldeffect mobility was increased when the gate insulator surface was treated with hexamethyldisilazane. However, in case of SSD OTFT, threshold voltage shift was not observed and the field-effect mobility was decreased.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1274-1274
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• 2008

In this report, the effect of substrate temperature on the electrical properties of ink-jet printed triisopropylsilyl (TIPS) pentacene organic thin-film transistors (OTFTs) has been investigated. The electrical properties such as mobility and on/off ratio were decreased as the substrate was heated above room temperature. The field-effect mobility of decreased from $10^{-2}cm^2/Vs$ to $10^{-5}cm^2/Vs$ and the on/off ratio decreased from $10^6$ to $10^4$ when the substrate temperature was heated from room temperature to 60$^{\circ}C$.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.654-656
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• 2008

We enhanced the conductivity of PEDOT-PSS by mixing with glycerol and fabricated the low contact resistance of source and drain[S/D] electrodes of OTFT with PEDOT-PSS by ink-jetting printing. The contact resistance was much smaller by seven times than Au with $200k{\Omega}$ at $V_G=-5V$. For the bottom contacted OTFTs, the performance was comparable to OTFTs with Au electrodes with the field effect mobility of $0.2\;cm^2/V s$.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.889-892
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• 2009

We have developed a practical printing technology for the gate electrode of organic thin film transistors(OTFTs) by combining screen-printing with wet-etching process using nano-silver ink as a conducting material. The screen-printed and wet-etched Ag electrode exhibited a minimum line width of ~5 um, the thickness of ~65 nm, and a resistivity of ${\sim}10^{-6}{\Omega}{\cdot}cm$, producing good geometrical and electrical characteristics for gate electrode. The OTFTs with the screen-printed and wet-etched Ag electrode produced the saturation mobility of $0.13cm^2$/Vs and current on/off ratio of $1.79{\times}10^6$, being comparable to those of OTFT with the thermally evaporated Al gate electrode.

• Polymer(Korea)
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• v.33 no.5
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• pp.397-406
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• 2009

We have fabricated source-drain electrodes for OTFTs using a screen-printing technique with carbon-black pastes as conductive paste. And effects of dispersants contents (SOP 10-40%) on the dispersity of carbon-black pastes and characteristics of screen-printed source-drain electrodes for OTFTs using two types of dispersants (DB-2150, DB-9077) were investigated. As contents of both dispersants were increased the dispersity of carbon-black mill-bases was improved, whereas the carbon-black pastes exhibited different dispersion characteristics. For the case of DB-2150, the dispersity of the pastes was improved with increasing dispersant content and the storage modulus G' in their rheology characteristics were reduced. But, for the DB-9077, the storage modulus G' of pastes were increased with dispersant content due to the flocculated network structure formed by interactions among carbon-black powders and dispersants. But, since this flocculated network structure of the pastes using DB-9077 resulted in the conduction path of carbon-black structures, the conductivities of screen-printed electrodes and mobilities of the OTFTs with them were better than those using pastes with DB-2150.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1122-1124
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• 2009

Organic thin-film transistors (OTFTs) were fabricated by using the transfer patterning method. In order to remove Au pattern easily, UV-curable polymer mold was surface treated. Au source/drain (S/D) pattern was transferred to insulator-coated substrate surface. Fabricated OTFTs were compared to OTFTs using vacuum-deposited Au S/D. Additionally, transistor diodes were characterized.