• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.21-24
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• 2003

In general, to enhance physical properties of PET-layered silicate nanocomposites $(P_{et}LSNs)$, it has been well known that the organic modifiers should introduce into gallery regions. However, the organic modifiers in$(P_{et}LSNs)$ may result in thermal decomposition by melt processing at high temperature, and it necessarily lead to deteriorate various physical properties of final products. Therefore, in this study, $(P_{et}LSNs)$ excluding and including organic modifiers were prepared by solution method $(S-P_{et}LSNs_{eom} and S-P_{et}LSNs_{iom})$ and we (focused on the effects of the organic modifiers in $P_{et}$ LSNs with exfoliation structure on the crystallization behaviors, the optical transparency, the thermal stability and the mechanical property. The absence and existence of organic modifiers in $S-P_{et}LSNs_{eom} and S-P_{et}LSNs_{iom}$ were investigated by EA and TGA, and nano-structure of silicate layers in $S-P_{et}LSNs$ was evaluated by using WXRD, SAXS and TEM. $S-P_{et}LSNs_{eom} and S-P_{et}LSNs_{iom}$ were mixed with neat PET as masterbatches by melt method $(M-P_{et}LSNs_{eom} and M-P_{et}LSNs_{iom})$, and also neat PET was mixed with organically modified layered silicates (OLS) by conventional direct melt method $(D-P_{et}LSNs) at 270^{\circ}C$. As results, it was found that $M-P_{et}LSNs_{eom}, M-P_{et}LSNs_{iom}, and D-P_{et}LSN$ showed a exfoliated structure and exhibited faster crystallization rate, better thermal stability and mechanical property than those of neat PET due to the dispersed and detaminated silicate layers in PET matrix. Whereas, considering organic modifiers effect, $M-P_{et}LSNs_{eom} and D-P_{et}LSN$ exhibited slower crystallization rate, poorer optical, thermal and mechanical properties, in comparison to $M-P_{et}LSNs_{eom}> due to the thermal decomposition of organic modifier in $D-P_{et}LSNs$ during melt method.

• Polymer(Korea)
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• v.32 no.6
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• pp.580-586
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• 2008

Copolyimides were synthesized from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 1,3-bis(3-aminophenoxy)benzene (BAPB) with different mole ratios of 2,2-bis[4-(4-aminophenoxy)pheny1]hexafluoropropane (BAPP). The solution cast film of poly(amic acid) (PAA) was heat treated at different temperatures to create copolyimide films. The PI copolymer films were found to exhibit good optical transparencies. The thermomechanical properties, morphology, and optical transparency of PI films were examined using fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (XRD), scanning electron microscopes (SEM), differential scanning calorimeter(DSC), thermo-gravimetric analyzer (TGA), universal tensile machine (UTM), and IN - Vis. spectrometer. The glass transition temperature ($T_g$), ultimate strength, and initial modulus linearly increased with increasing BAPP mole fraction. However, thermal stability($T_D{^i}$) of the copolyimide remains constant regardless of BAPP loadings. It was found, however, that the optical transparency decreases slightly upon increasing the BAPP content because of the formation of the charge transfer complexes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.309-309
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• 2009

In-Ga-Zn-O (IGZO) has drawn much attention as a compatible material for transparent thin film transistors (TTFT) channel layer due to its high mobility and optical transparency at low processing temperatures. In this work, we investigated the effect of oxygen ambient on structural, electrical and optical properties of amorphous In-Ga-Zn-O (IGZO) thin films by using pulsed laser deposition (PLD). The films were deposited at various oxygen pressures and the structural, electrical and optical properties were investigated. X-ray diffraction (XRD) analysis showed that amorphous IGZO films were grown at all oxygen pressures. The surface morphology and optical properties with various oxygen pressures were studied by field emission scanning electron microscopy (FE-SEM) and UV-VIS spectroscopy, respectively. The grain boundary was observed more apparently and the calculated optical band gap became larger as oxygen pressure increased. To examine the electrical properties, Hall-effect measurements were carried out. The films showed high mobility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.305-306
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• 2006

Ga-doped and Al-doped ZnO thin films were fabricated via a sol-gel technique and electrical and optical properties of the films were investigated. Film deposition was performed by spin coating at 4000 rpm for 30 s on $SiO_2$ glass substrate FE-SEM was used to obtain the surface morphology images and the film thickness Four-point probe and UV-VIS spectrophotometer were used to measure the sheet resistance and the optical transparency, respectively.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.98-103
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• 2008

The glass for crystalline PV module fabrication should have high thermal and mechanical resistance to environmental also have high transparency. In this paper, we analyze the optical characteristics of glasses for photovoltaic module application. The transmittance of several glasses are measured. The effects of texturing on low iron glass, glass thickness, anti-reflective glass, photocatalyst-treated glass and special glass are compared each other. Then this will give some information to select PV glass for manufacturing. The detailed analysis is described in the following paper.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.2
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• pp.119-123
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• 2006

This work presents the fabrication and characteristics of $Bi_2O_3/Si$ heterojunction prepared by rapid thermal oxidation technique without any postdeposition annealing condition. The bismuth trioxide film was deposited onto monocrystalline Si and glass substrates by rapid thermal oxidation of bismuth film with aid of halogen lamp at $500^{\circ}C/\;45$ s in static air. The structural, optical and electrical properties of $Bi_2O_3$ film were investigated and compared with other published results. The structural investigation showed that the grown films are polycrystalline and multiphase (${\alpha}-Bi_2O_3$ and ${\beta}-Bi_2O_3$). Optical properties revealed that these films having direct optical band gap of 2.55 eV at 300 K with high transparency in visible and NIR regions. Dark and illuminated I-V, CV, and spectral responsivity of $Bi_2O_3/Si$ heterojunction were investigated and discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.179-180
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• 2008

In this paper, we studied the optical property of transparent glasses for photovoltaic module manufacturing. The glass should have high mechanical and chemical resistance from outside environmental. Also optical transparency is a key requirement for better electrical performance. In here, we examine several kinds of transparent glasses and special purpose ones. This would give some real information for understanding PV module. The further analysis is described in the following paper.

• Journal of the Semiconductor & Display Technology
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• v.13 no.1
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• pp.35-41
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• 2014

UV curable transparent hard coating materials have been developed to improve the mechanical and optical properties of PET substrate. The coating materials were synthesized using various urethane acrylate oligomers, monomers, photo initiators, and leveling agents. The materials were coated on PET substrates and UV cured. The hard coated PET films were shown to have the good scratch resistance and transparency. When the urethane acrylate oligomer with more functional groups was introduced into the coating solution, the mechanical and optical properties were improved. However the higher concentration of 9-functional oligomer resulted in the decrease of workability. The addition of trimethylolpropane ethoxylate$(EO/OH)_9$ triacrylate(TMPETA) to coating solution improved the workability and properties. As a result, the UV cured film from the formulation of urethane acrylate oligomer with 9-functional groups, TMPETA as a monomer, IRACURE 754 as a photo initiator and BYK-340 as a leveling agent showed the best mechanical and optical properties in this study.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.4
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• pp.529-534
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• 1986

A holographic iverse filter has been used for optical image deblurring by modeling the PSF(point spread function)of blurred system. This paper presents the optical image restoration of an accidentally blurred photograph by using a simgle inverse filter which is obtained from a blurrec PSF by analyzing the Fourier spectrum of the supposely defocused photograph itself. The filter, a positive transparency having gamma of 2, has amplitude and phase informations simulatneously.

• Korean Journal of Optics and Photonics
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• v.14 no.5
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• pp.483-490
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• 2003

We have analyzed theoretically optical pulse propagation in a coherent atomic medium for amplification without inversion (AWI), which is achieved by adding incoherent optical pumping to a typical EIT system. In order to explain experimental results [Kim et al., J. Phys. B, 36, 2671(2003)] to control the group velocity of the optical pulse by changing pumping power, we established a 5-level atomic system and applied density matrix equations. This AWI model system is different from previous AWI systems from the viewpoint of using two levels for incoherent optical pumping isolated optically from the EIT (electromagentically induced transparency) system so that more atoms can participate in pulse speed control. We have found that population transfer by collisions between ground states plays a decisive role for efficient AWI, and more atoms are effective for slowing the pulse. Our numerical results are in good agreement qualitatively with experimental results.