• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.55-60
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• 2006

Thermally stable and solution-processable poly(N-arylcarbazole-alt-aniline) copolymers with high structural integrity were synthesized in good yields via palladium-catalyzed polycondensation of aniline with corresponding N-arylcarbazole monomers such as N-(2-ethylhexyloxyphenyl)-3,6-dibromocarbazole,bis[6-bromo-N-(2-ethylhexyloxyphenyl)carbazole-3-yl] and N-(4-(2-ethylhexyl)-3,5-dibromomethylene-phenyl) carbazole, respectively. The optical and electrochemical properties of these copolymers were measured and compared with those of poly(N-alkylcarbazole-alt-aniline) copolymer. All synthesized poly(N-arylcarbazole-alt-aniline) copolymers showed maximum UV-Vis absorption peaks at around 300 nm in THF solution, and exhibited maximum photoluminescence peaks in the blue emission range from 430 to 460 nm. It was also found that poly(N-arylcarbazole-alt-aniline) copolymers had wider band gap energy than poly(N-alkylcarbazole-alt-aniline) copolymer.

• 대한화학회지
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• 제33권5호
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• pp.504-509
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• 1989

N,N'-dimethylethylenediamine-N,N'-di-${\alpha}$-butyric acid(dmedba)와 세자리 아미노산과의 코발트(III) 착물인 [Co(dmedba)(L-aa)] (L-aa = S-methyl-L-cysteine, L-methionine, L-glutamic acid, L-aspartic acid)는$ s-cis-[Co(dmedba)Cl_2]-^ 착물과 아미노산과의 반응으로부터 얻었다. 아미노산들은 [Co(dmedda)(L-dd)] 착물과 같이 아민과 카르복실그룹을 통하여 배위되었다. 이 착물들의 구조는 ^1H-NMR, IR, UV$ 스펙트럼 데이타와 원소분석으로 확인하였다.

• Macromolecular Research
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• 제12권4호
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• pp.352-358
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• 2004

For their application as one-component photoresists, we prepared epoxy terpolymers containing oxime-urethane and benzophenone groups by the radical polymerization of glycidyl methacrylate (GMA), metha-cryloxyethyl benzophenoneoxime urethane (MBU), and N-(4-benzoyl)phenylmaleimide (BPMI). The terpolymer composition was optimized to provide the most photosensitive photoresist. The photo-decomposition reaction of the oxime-urethane groups in the terpolymer was monitored by UV absorption spectroscopy, and the photo-crosslinking reaction of the epoxy terpolymer was observed by measuring the normalized thickness. The photosensitivity of the epoxy terpolymer increased as the amount of BPMI and MBU units increased up to 16 and 24 mol%, respectively. Among the terpolymers we prepared, terpolymer T-II(contents of GMA, MBU, BPMI are 75, 19, 6.1 mole%, respectively) exhibited the highest photosensitivity ( $D_{c}$ $^{0.5}$ = 430 mJ/$\textrm{cm}^2$) and had a moderate contrast (${\gamma}$$^{p}$ = 1.23). Negative-tone micropatterns having a line width of ca. 10 ${\mu}{\textrm}{m}$ were obtained by developing the system with chloroform.m.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.199-203
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• 2012

A modified sol-gel method and $N_2$-plasma treatment were used to prepare bulk and surface doped N-$TiO_2$, respectively. XRD, TEM, UV-vis spectroscopy, $N_2$ adsorption, Elemental Analyzer, Photoluminescence, and XP spectra were used to characterize the prepared $TiO_2$ samples. The N doping did not change the phase composition and particle sizes of $TiO_2$ samples, but increased the visible light absorption. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activity of surface doped N-$TiO_2$ prepared by $N_2$-plasma was much higher than that of bulk doped N-$TiO_2$ prepared by sol-gel method. The possible mechanism for the photocatalysis was proposed.

• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2213-2216
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• 2009

A novel carbazole functionalized bis-$\beta$-diketone type organic ligand, 1,1′-(2,6-bispyridyl)bis-3-(9-ethylcarbazole- 3-yl)-1,3-propanedione ($H_2L$) and its corresponding lanthanide complexes $Eu_2(L)_3\;and\;Tb_2(L)_3$ were successfully prepared. The ligand and complexes were characterized in detail based on FT-IR spectra, $^1H$ NMR and elemental analysis. The observed UV-Vis absorption and photoluminescence properties of the complexes were investigated, it shows that the Eu(III) and Tb(III) ions can be sensitized efficiently by the ligand ($H_2L$) to some extent, in particular, the complex $Tb_2(L)_3$ exhibits a more excellent luminescence property than the Eu(III) complex. Meanwhile, the introduction of the carbazole moiety can enlarge the $\Pi$-conjugated system of the ligand and enhance the luminescent intensity of the complexes. The results show that the complexes would be used as excellent luminescent materials.

• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.842-846
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• 2008

Layer-by-layer assembled multilayers of poly(ethersulfone)s were deposited on the surface of Nafion membrane for the application of direct methanol fuel cells (DMFC). Aminated poly(ethersulfone) (APES) and sulfonated poly(ethersulfone) (SPES) were used as a polycation and a polyanion for fabrication of the multilayer films. UV/Vis absorption spectroscopy verified a linear build-up of the multilayers of APES and SPES on the surface of Nafion. Thin multilayer films deposited on the Nafion membrane enabled methanol permeability of the membrane to decrease by 78% in comparison with the pristine Nafion. The performance of DMFCs in concentrated methanol was highly enhanced by using the multilayer modified Nafion.

• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.761-766
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• 2008

Photoresponsive arylether dendrimers Bis-azo-Gn(3,5) 1a-1c and Bis-azo-Gn(3,4,5) 2a-2c (n = 1-3) with an azobenzene unit at the core and several vinyl groups (3,5-bis(but-3-enyloxy)phenyl groups or 3,4,5-tris(but-3- enyloxy)phenyl groups) at the periphery have been prepared. Their structures and reversible trans-cis isomerization behaviors have been investigated by $^1H$-NMR, $^{13}C$-NMR, MALDI-TOF-Mass, and UV-vis spectra. All six azobenzene-cored dendrimers carried out very fast trans $\rightarrow$ cis photoisomerization on irradiation of 350 nm light and reached to the photostationary state within 180 s. During the dark incubation, slow thermal back reversion from cis to trans form is observed for all six dendrimers and is completed within 3 days for 1a-1c and 1 day for 2a-2c. Isomerization efficiency decreases with increasing generation. However, the initial reaction rates of both trans $\rightarrow$ cis photochemical isomerization and cis $\rightarrow$ trans thermal isomerization increases significantly with increasing generation for dendrimers for 1a-1c but only slightly for 2a-2c.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.575-580
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• 2014

We uniformly coated Eu(III)- and Tb(III)-doped yttrium oxide onto the surface of $SiO_2$ spheres and then characterized them by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction crystallography and UV-Visible absorption. 2D and 3D photoluminescence image map profiles were reported for the core-shell type structure. Red emission peaks of Eu(III) were observed between 580 to 730 nm and assigned to $^5D_0{\rightarrow}^7F_J$ (J = 0 - 4) transitions. The green emission peaks of Tb(III) between 450 and 650 nm were attributed to the $^5D_4{\rightarrow}^7F_J$ (J = 6, 5, 4, 3) transitions. For annealed samples, Eu(III) ions were embedded at a $C_2$ symmetry site in $Y_2O_3$, which was accompanied by an increase in luminescence intensity and redness, while Tb(III) was changed to Tb(IV), which resulted in no green emission.

• Bulletin of the Korean Chemical Society
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• 제34권4호
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• pp.1170-1174
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• 2013

Benzodithiophene based organic semiconducting polymer was designed and synthesized by stille coupling reaction. The structure of polymer was confirmed by NMR and IR. The weight average molecular weight ($M_w$) of polymer was 8,400 using GPC with polydispersity index of 1.4. The thermal, optical and electrochemical properties of polymer were characterized by TGA and DSC, UV-vis absorption and cyclic voltammetry. OTFT device using PBDT-10 exhibited the mobility of $7.2{\times}10^{-5}\;cm^2\;V^{-1}\;s^{-1}$ and $I_{on}/I_{off}$ of $2.41{\times}10^3$. The film morphology and crystallinity of PBDT-10, was studied using AFM and XRD.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2883-2888
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• 2013

To enhance the power conversion efficiency of dye-sensitized solar cell (DSSC), the surface of titanium dioxide ($TiO_2$) photoelectrode was modified by hydroxylation treatment with $NH_4OH$ solution at $70^{\circ}C$ for 6 h. The $NH_4OH$ solutions of various concentrations were used to introduce the hydroxyl groups on $TiO_2$ surface. As the concentration of $NH_4OH$ was increased, the short-circuit current density ($J_{SC}$) value and conversion efficiency of solar cells were increased because the amount of adsorbed dye molecules on $TiO_2$ surface was increased. As a result of the surface modification to introduce hydroxyl groups, the concentration of adsorbed dye on the $TiO_2$ surface could be improved up to 32.61% without the changes of morphology, surface area and pore volume of particles. The morphology, the specific surface area, the pore volume and the chemical states of $TiO_2$ surface were characterized by using FE-SEM, $N_2$ adsorption-desorption isotherms and XPS measurements. The amount of adsorbed dye and the performance of fabricated cells were analyzed by using UV-Vis absorption spectroscopy and solar simulator.