• Proceedings of the Materials Research Society of Korea Conference
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• 2007.05a
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• pp.13.2-13.2
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• 2007

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.36.2-36.2
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• 2009

In this work, the high power CW Nd:YAG laser has been used for thermal treatment of inkjet printed Ag films-involving eliminating organic additives (dispersant, binder, and organic solvent) of Ag ink and annealing Ag nanoparticles. By optimizing laser parameters, such as laser power and defocusing value, the laser energy can totally be converted to heat energy, which is used to thermal treatment of inkjet printed Ag films. This results in controlling the microstructures and the resistivity of films. We investigated the thermal diffusion mechanisms during laser annealing and the resulting microstructures. The impact of high power laser annealing on microstructures and electrical characteristic of inkjet printed Ag films is compared to those of the films annealed by a conventional furnace annealing. Focused ion beam (FIB) channeling image shows that the laser annealed Ag films have large columnar grains and dense structure (void free), while furnace annealed films have tiny grains and exhibit void formation. Due to these microstructural characteristics of laser annealed films, it has better electrical property (low resistivity) compared to furnace annealed samples.

• Korean Journal of Materials Research
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• v.17 no.4
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• pp.215-221
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• 2007

The effect of $CF_4$ plasma treatment condition on the interfacial adhesion energy of inkjet printed Ag/polyimide system is evaluated from $180^{\circ}$ peel test by calculating the plastic deformation energy of peeled metal films. Interfacial fracture energy between Ag and as-received polyimide was 5.5 g/mm. $CF_4$ plasma treatment on the polyimide surface enhanced the interfacial fracture energy up to 17.6 g/mm. This is caused by the increase in the surface roughness as well as the change in functional group of the polyimide film due to $CF_4$ plasma treatment on the polyimide surface. Therefore, both the mechanical interlocking effect and the chemical bonding effect are responsible for interfacial adhesion improvement in ink jet printed Ag/polyimide systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.550-550
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• 2007

Inkjet printed silver films were fabricated using nano particles with the size of ~ 20 nm. We can obtain very good conducting silver films with the resistivity of $7.3\;{\mu}{\Omega}{\cdot}cm$ even though they were sintered at the very low temperature of $200^{\circ}C$. The electrical and mechanical properties of inkjet printed silver lines were measured with the sintering time and analyzed with the micro-structural development. The measured resistivity of inkjet printed Ag films were $57.4\;{\sim}\;7.3\;{\mu}{\Omega}{\cdot}cm$. And their hardness and Young's modulus were 0.98 ~ 1.72 GPa and 32 ~ 71 GPa, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.667-668
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• 2011

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.603-609
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• 2013

In this paper, we describe the analysis of inkjet-printed silver (Ag) patterns on epoxy-coated substrates according to several reliability evaluation test method guidelines for conventional printed circuit boards (PCB). To prepare patterns for the reliability analysis, various regular test patterns were created by Ag inkjet printing on flame retardant 4 (FR4) and polyimide (PI) substrates coated with epoxy for each test method. We coated the substrates with an epoxy primer layer to control the surface energy during printing of the patterns. The contact angle of the ink to the coated epoxy primer was $69^{\circ}$, and its surface energy was 18.6 $mJ/m^2$. Also, the substrate temperature was set at $70^{\circ}C$. We were able to obtain continuous line patterns by inkjet printing with a droplet spacing of $60{\mu}m$. The reliability evaluation tests included the dielectric withstanding voltage, adhesive strength, thermal shock, pressure cooker, bending, uniformity of line-width and spacing, and high-frequency transmission loss tests.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.95-96
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• 2012

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.551-552
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• 2006

This study was attended to demonstrate synthesis of silver nanoparticles stabilized with polymer and their applicability to printed electronics. Silver nanoparticles were synthesized by reduction of silver nitrate in aqueous solution in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer. The ink used here is composed of 50 wt% Ag NP, 15 wt% humectant and then were printed on polyimide film. Particle deposit morphologies were controlled by varying the ink compositions. Printed silver patterns and dots were cured on a convection oven in air at $300^{\circ}C$ for 60 min. The printed patterns show good shape definition and the resistivity of the printed films is about $5{\mu}{\Omega}{\cdot}cm$.

• Journal of Sensor Science and Technology
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• v.33 no.1
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• pp.24-29
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• 2024

Inkjet printing technology is used to mass-produce displays and electrochemical sensors by dropping tens of pico-liters or less of specific-purpose ink through nozzles, just as ink is sprayed and printed on paper. Unlike the deposition method for vaporizing material in a vacuum, inkjet printing technology can be used for processing even under general atmospheric pressure and has a cost advantage because the material is dissolved in a solvent and used in the form of ink. In addition, because it can only be printed on the desired part, masks are not required. However, a technical shortcoming is the difficulty for commercialization, such as uniformity for forming the thickness and coffee ring effect. As sizes of devices decrease, the need to print electrodes with precision, thinness, and uniformity increases. In this study, we improved the printing and processing conditions to form a homogeneous electrode using Ag ink (DGP-45LT-15C) and applied this for patterning to fabricate a heat sensor. Upon the application of voltage to the heat sensor, the model with an extended width exhibited superior heat performance. However, in terms of sheet resistance, the model yielded an equivalent value of 21.6 Ω/□ compared to the ITO.

• Journal of Information Display
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• v.12 no.4
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• pp.213-217
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• 2011

Printing technologies were applied to fabricate a flexible organic thin-film transistor (OTFT) backplane for electrophoretic displays (EPDs). Various printing processes were adopted to maximize the figures of each layer of OTFT: screen printing combined with reverse offset printing for the gate electrodes and scan bus lines with Ag ink, inkjet for the source/drain electrodes with glycerol-doped Poly (3,4-ethylenedioxythiophene): Poly (styrenesulfonate) (PEDOT:PSS), inkjet for the semiconductor layer with Triisopropylsilylethynyl (TIPS)-pentacene, and screen printing for the pixel electrodes with Ag paste. A mobility of $0.44cm^2/V$ s was obtained, with an average standard deviation of 20%, from the 36 OTFTs taken from different backplane locations, which indicates high uniformity. An EPD laminated on an OTFT backplane with $190{\times}152$ pixels on an 8-in panel was successfully operated by displaying some patterns.