• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.128-132
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• 2013

L-Arginine semi-oxalate (LASO) single crystal has been grown by solution growth technique at room temperature. The crystal structure and lattice parameters were determined for the grown crystal by single crystal X-ray diffraction studies. Photoluminescence studies confirm the violet fluorescence emission peak at 395 nm. Optical constants like band gap, refractive index, reflectance, extinction coefficient and electric susceptibility were determined from UV-VIS-NIR spectrum. The dielectric constant, dielectric loss and ac conductivity of the compound were calculated at different temperatures and frequencies to analyze the electrical properties. The solid state parameters such as plasma energy, Penn gap, Fermi energy and polarizability were calculated to analyze second harmonic generation (SHG). Nonlinear optical property was discussed to confirm the SHG efficiency of the grown crystal.

• Journal of the Korean Chemical Society
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• v.47 no.5
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• pp.447-459
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• 2003

Generalized 2D correlation spectroscopy has been applied extensively to the analysis of spectral data sets obtained during the observation of a system under some external perturbation. It is used in various fields of spectroscopy including IR, Raman, UV, fluorescence, X-ray diffraction, and X-ray absorption spectroscopy (XAS) as well as chromatography. 2D hetero-spectral correlation analysis compares two completely different types of spectra obtained for a system under the same perturbation. Because of the wide range of applications of this technique, it has become one of the standard analytical techniques for the analytical chemistry, physical chemistry, biochemistry, and so on, and for studies of polymers, biomolecules, nanomaterials, etc. In this paper, we will introduce the principle of generalized 2D correlation spectroscopy and its applications that we have studied.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3272-3278
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• 2010

Synthesis and structural characterization of peripherally ferrocene-substituted zinc phthalocyanine (ZnPc-Fc) were carried out for efficient far-red/near-IR performance in dye-sensitized nanostructured $TiO_2$ solar cells. Incorporating ferrocene into phthalocyanine strongly improved the dye solubility in polar organic solvents, and reduced surface aggregation due to the steric effect of bulky ferrocene substituents. The involvement of electron transfer reaction pathways between ferrocene and phthalocyanine in ZnPc-Fc was evidenced by completely quenched fluorescence from S1 state (< 0.08% vs ZnPc). Strong absorption bands at 542 and 682 nm were observed in the transient absorption spectroscopy of ZnPc-Fc in DMSO, which was excited at a 670 nm laser pulse with a 15 ps full width at half maximum. Also, the excited state absorption signals at 450 - 600 and 750 - 850 nm appeared from the formation of charge separated state of phthalocyanine's anion. The lifetime of the charge separate state in ZnPc-Fc was determined to be $170{\pm}8$ ps, which was almost 17 times shorter than that of the ZnPc.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2010.03a
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• pp.49-50
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• 2010

The near-infrared absorbing donor-acceptor chromophores have been investigated by varying the electron donating and accepting molecular moiety. A series of near-infrared absorbing chromophores were offered narrow and intense absorption band in a various organic solvents. The dyes synthesised were, however, strongly bathochromic shift which extended well into the near-infrared region. The functional uses of dyes are vast in number, and it is convenient to classify them in some way. In all cases, it is the $\Pi$-chromophore that plays a major role in the functional application. "Light absorption" is of course the most commonly used property of a dye chromophore, and it can be employed directly, e.g. in light filters and optical data recording, or it can be used to drive further functional processes, e.g. fluorescence, photochromism, photosensitization.

• Proceedings of the KSRS Conference
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• v.1
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• pp.90-93
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• 2006

The first Geostationary Ocean Color Imager (GOCI) onboard its Communication Ocean and Meteorological Satellite (COMS) is scheduled for launch in 2008. GOCI includes the eight visible-to-near-infrared (NIR) bands, 0.5km pixel resolution, and a coverage region of 2500 ${\times}$ 2500km centered at 36N and 130E. GOCI has had the scope of its objectives broadened to understand the role of the oceans and ocean productivity in the climate system, biogeochemical variables, geological and biological response to physical dynamics and to detect and monitor toxic algal blooms of notable extension through observations of ocean color. The special feature with GOCI is that like MODIS, MERIS and GLI, it will include the band triplets 660-680-745 for the measurements of sun-induced chlorophyll-a fluorescence signal from the ocean. The GOCI will provide SeaWiFS quality observations with frequencies of image acquisition 8 times during daytime and 2 times during nighttime. With all the above features, GOCI is considered to be a remote sensing tool with great potential to contribute to better understanding of coastal oceanic ecosystem dynamics and processes by addressing environmental features in a multidisciplinary way. To achieve the objectives of the GOCI mission, we develop the GOCI Data Processing System (GDPS) which integrates all necessary basic and advanced techniques to process the GOCI data and deliver the desired biological and geophysical products to its user community. Several useful ocean parameters estimated by in-water and other optical algorithms included in the GDPS will be used for monitoring the ocean environment of Korea and neighbouring countries and input into the models for climate change prediction.

• Korean Journal of Materials Research
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• v.30 no.1
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• pp.1-7
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• 2020

Doping or incorporation with exotic elements are two manners to regulate the optoelectronic properties of transparent conducting (TCO) cadmium oxide (CdO). Nevertheless, the method of doping host CdO by CdTe semiconductor is of high importance. The structural, optical, and electrical properties of CdTe-doped CdO films are studied for the sake of promoting their conducting parameters (CPs), including their conductivity, carrier concentration, and carrier mobility, along with transparency in the NIR spectral region; these are then compared with the influence of doping the host CdO by pure Te ions. X-ray fluorescence (XRF), X-ray diffraction (XRD), optical absorption spectroscopy, and electrical measurements are used to characterise the deposited films prepared by thermal evaporation. Numerous results are presented and discussed in this work; among these results, the optical properties are studied through a merging of concurrent BGN (redshift) and BGW (blue shift) effects as a consequence of doping processes. The impact of hydrogenation on the characterisations of the prepared films is investigated; it has no qualitative effect on the crystalline structure. However, it is found that TCO-CPs are improved by the process of CdTe doping followed by hydrogenation. The utmost TCO-CP improvements are found with host CdO film including ~ 1 %Te, in which the resistivity decreases by ~ 750 %, carrier concentration increases by 355 %, and mobility increases by ~ 90 % due to the increase of N_carr. The improvement of TCO-CPs by hydrogenation is attributed to the creation of O-vacancies because of H₂ molecule dissociation in the presence of Te ions. These results reflect the potential of using semiconductor CdTe -doped CdO thin films in TCO applications. Nevertheless, improvements of the host CdO CPs with CdTe dopant are of a lesser degree compared with the case of doping the host CdO with pure Te ions.