• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.403-405
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• 2009

본 연구에서는 염료태양전지의 제작 시 고가의 TCO전극을 사용하지 않고 간단히 광전극을 대체할 수 있는 방법으로 메쉬전극을 이용하는 TCO-less 염료태양전지를 제작하였다. 메쉬전극을 이용한 TCO-less 염료태양전지의 구조는 "Glass / 메쉬전극($TiO_2$를 딥코팅 한 후 염료를 흡착시킴) / 전해질 / 멤브레인 필터 / 상대전극(Pt-coated TCO) / Glass" 로 구성된다. 제작된 샘플의 광전변환 효율은 약 1.5% 였으며 fill factor는 0.55로 나타났다. 향후 계획으로 효율을 향상 시킬 수 있는 방법을 도입하여 광전류밀도와 fill factor를 개선하는 연구를 진행할 예정이다.

• Journal of Sericultural and Entomological Science
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• v.32 no.1
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• pp.58-67
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• 1990

견 피브로인 막을 통한 투과실험으로, 종전의 견섬유로는 얻을 수 없었던 투과 및 확산거동에 대하여, Dual mechanism을 적용하여 고찰하였으며, 아울러 염료의 구조가 이러한 물리화학적 성질에 가지는 영향에 관해서 고찰한 결과를 요약하면 다음과 같다. 1) 전체적인 확산계수 $D_{(c)}$는 주로 Langmuir-type 확산계수 $D_{L}$에 의해서 결정된다. 2) 농도에 따른 확산계수의 조사에서 Dye I (monobasic dye)에서는 뚜렷한 최대치가 관찰되었으나, Dye III(trisulfonic acid dye)에서 $D_{p}$는 거의 의미가 없는 것으로 나타났다. 3) 견 피브로인에 있어서 산성염료의 확산은 sulfonic acid group의 도입에 따라 정점 느리게 되고, $D_{L}$은 온도의 증가에 따라 더 큰 값을 나타냈다. 4) 염료 음이온의 하전수가 클수록 확산계수는 chemical potential gradient model에 더욱 더 가깝게 된다. 5) 투과의 활성화 에너지는 sulfonic acid group의 도입에 따라 감소되었다.다.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.210-216
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• 2015

Adsorption of brilliant blue FCF dye using coal based the granular activated carbon from aqueous solution was investigated. Batch experiments were carried out as a function of the adsorbent dose, initial concentration, contact time and temperature. The equilibrium adsorption data were fitted to Langmuir, Freundlich and Temkin models. The results indicate that Freundlich model provides the best correlation of the experimental data. Base on the estimated Freundlich constant (1/n = 0.129~0.212), this process could be employed as an effective treatment method. Adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetic equations. It was shown that the pseudo-second-order kinetic equation could describe well the adsorption kinetics. The negative Gibbs free energy value (-4.81~-10.33 kJ/mol) and positive enthalpy value (+78.59 kJ/mol) indicated that the adsorption was a spontaneous and endothermic process.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.488-492
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• 2023

In this study, a carbon film derived from a polymer/lignin composite precursor was produced by a carbonization cycle with a controlled temperature profile. The feasibility of successful formation of the carbon film using the carbonization cycle was monitored. The adsorption behavior of the carbon film toward various molecules, such as nonpolar and polar organic molecules, and dyes was investigated using ultraviolet/visible (UV/Vis) spectroscopy compared with that of carbonized lignin. Cyclic voltammetry (CV) analysis proved that a robust carbon film was prepared by the carbonization cycle. It was also demonstrated that the carbonized lignin and carbon film showed adsorption capability toward all types of organic molecules, in particular organic dyes, owing to the carbonized lignin. This work provides important information for future relevant research.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.458-465
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• 2020

Isotherms, kinetics and thermodynamic properties for adsorption of acid fuchsin (AF) dye by activated carbon were carried out using variables such as dose of adsorbent, pH, initial concentration and contact time and temperature. The effect of pH on adsorption of AF showed a bathtub with high adsorption percentage in acidic (pH 8). Isothermal adsorption data were fitted to the Freundlich, Langmuir, and Dubinin-Radushkevich isotherm models. Freundlich isothem model showed the highest agreement and confirmed that the adsorption mechanism was multilayer adsorption. It was found that adsorption capacity increased with increasing temperature. Freundlich's separation factor showed that this adsorption process was an favorable treatment process. Estimated adsorption energy by Dubinin-Radushkevich isotherm model indicated that the adsorption of AF by activated carbon is a physical adsorption. Adsorption kinetics was found to follow the pseudo-second-order kinetic model. Surface diffusion at adsorption site was evaluated as a rate controlling step by the intraparticle diffusion model. Thermodynamic parameters such as activation energy, Gibbs free energy, enthalpy entropy and isosteric heat of adsorption were investigated. The activation energy and enthalpy change of the adsorption process were 21.19 kJ / mol and 23.05 kJ / mol, respectively. Gibbs free energy was found that the adsorption reaction became more spontaneously with increasing temperature. Positive entropy was indicated that this process was irreversible. The isosteric heat of adsorption was indicated physical adsorption in nature.

• Clean Technology
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• v.23 no.2
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• pp.188-195
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• 2017

This research studied the adsorption of basic dye, Basic Blue 3 (BB3) by using coal-based granular activated carbon (C-GAC) from aqueous solution. All experiments were performed in batch processes, and adsorption parameters such as C-GAC dosage, contact time, initial dye concentration and temperature were evaluated. The removal efficiency of BB3 was increased with increasing the C-GAC dosage and 100% of initial concentration, $50mg\;L^{-1}$ was removed above 0.2 g of C-GAC. Also, the time to reach equilibrium depended on the initial dye concentration. According to the Langmuir model, the maximum uptakes of C-GAC were calculated to be 66.45, 84.97 and $87.19mg\;g^{-1}$ at 25, 35 and $45^{\circ}C$, respectively. In addition, thermodynamic parameters such as Gibbs free energy change, enthalpy change and entropy change were investigated.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.89-89
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• 2011

Cellulose섬유의 염색시 섬유가 물속에 침지되면 섬유표면은 음전하가 형성되어, 용액 속에서 음이온으로 존재하는 염료와의 반발력으로 인해 염료가 섬유에 접근하기가 어려워지며 따라서 염색이 원활하게 이루어지지 않는다. 그러나 염욕에 염화나트륨(sodium chloride, NaCl)이나 망초 즉, 황산나트륨(Glauber's salt, sodium sulfate, Na2SO4)과 같은 전해질을 첨가하면, 양이온인 sodium 이온이 섬유표면과 음이온 염료사이의 반발력을 감소시킨다. 따라서 음이온의 염료는 섬유표면에 접근할 수 있고, 고유한 인력으로 염색이 가능하게 된다. 현재 Cellulose섬유의 상업적인 반응성염료 염색공정뿐만 아니라 최근 연구에서는 전해질 중 대부분 분말망초를 대부분 사용하고 있다. 그러나 분말망초는 별도의 용해과정이 필요할 뿐 아니라, 과량 사용시 용해되지 않은 분말이 섬유 표면에 흡착될 경우 불균염을 초래할 우려 등의 단점이 있다. 이와 같이 작업효율성을 향상시키고 염색을 효율적으로 진행시키기 위해 최근 액상형의 망초가 도입되고 있다. 이 연구에서는 분말 및 액상 망초를 조제로 사용하여 3종류의 Cellulose섬유를 반응성염료로 염색하였다. 담색, 중색, 농색 3가지 염료 농도에 대해 투입하는 망초의 type에 따라 각각의 Cellulose섬유별 균염성 정도에 대하여 비교해 보았다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.68.2-68.2
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• 2010

Dye-sensitized solar cells (DSSC) show great promise as an inexpensive alternative to conventional p-n junction solar cells. Investigations into the various factors influencing the photovoltaic efficiency have recently been intensified. The conventional absorber electrode in DSSC is composed of compacted or sintered $TiO_2$ nanopowder that carries an anchored organic dye. The absorbance of incident light in the DSC is realized by specifically engineered dye molecules placed on the semiconductor electrode surface ($TiO_2$). The dye absorbs light at wavelengths up to about 920nm, the energy of the exited state of the molecule should be about 1.35eV above the electronic ground state corresponding to the ideal band gap of a single band gap solar cell. The dye molecules ar adhered onto the nanostrutured $TiO_2$ electrode by immersing the sintered electrode into a dye solution, typically 3mM in alcohol, for a long enough period to fully impregnate the electrode. However, the concentrations of the dye is slightly changed due to the evaporation of the alcohol. The dye is more expensive than other materials in DSSC and related to the efficiency of DSSC. Therefore, the concentrations of the dye should be carefully measured. In this study, we investigated to the dye loading on fired $TiO_2$ powder as a function of temperature by the TG-DTA and the dye solution by UV-visible spectroscopy after the impregnation process. The dye loading is related to the porosity of the nanostructured $TiO_2$ electrode.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.22-22
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• 2010

최근 염료감응형 태양전지(DSSC)는 광변환효율 측면에서 향상 가능성이 높으며, 전기화학적 반응을 바탕으로 하므로 생산단가가 낮아 차세대 태양전지로 관심을 모우고 있다. 염료감응형 태양전지에 있어서 주요 구성성분 중의 하나는 다공성 산화물 광전극 재료이다. 다양한 반도체 물질과 비교할 때 $TiO_2$는 전도대의 위치와 전자이동성 면에서 비교적 적합하며, 유기물과의 흡착성 및 안정성 측면에서 대단히 우수하다. 염료감응형 태양전지의 $TiO_2$ 광전극이 갖추어야 할 요건은 표면적이 넓어서 염료 흡착량이 많아야 하며, 전자전달 및 전해질 이동을 위한 효율적 구조이어야 한다. $TiO_2$ 광전극 제작을 위한 재료로서는 나노입자가 널리 이용되며, 입자의 크기는 20 nm 부근이 적합한 것으로 알려져 있다. 본 발표에서는 나노입자 외에 나노막대, 나노섬유, 나노튜브, inverse-opal 구조 등과 같이 지금까지 연구되고 있는 $TiO_2$ 나노구조 관련연구를 소개 한다. 한편으로 효율적 전극구조를 제작하려면 $TiO_2$ 나노구조 제어 외에도, 투명전극과 $TiO_2$ 전극과의 계면층(interfacial layer) 제어, 빛의 효율적 이용을 위한 산란층(scattering layer) 및 $TiO_2$ 전극에서 전해질로의 전자손실 억제를 위한 blocking layer 도입 등이 필요하다. 이에 대한 기본개념을 설명하고 다른 연구자의 연구결과를 소개한다. 본 연구실의 연구 결과인, 메조 포러스 구조, 다공성 속빈구 구조와 구형구조체를 합성하고 이를 염료감응형 태양전지에 응용한 내용을 소개한다. 다공성 속빈구의 경우, 산란층으로 대단히 우수한 결과를 나타내었고, 다공성 구형구조체는 광전극 주재료로 적합한 특성을 나타내었다. 즉, 다공성 구형구조체를 적용한 광전극은 표면적이 대단히 넓고 또한 효율적 동공구조가 형성되어 전해질 이동에도 매우 효율적이다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.60.2-60.2
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• 2010

A $TiO_2$ films in dye-sensitized solar cells was fabricated using $TiO_2$ colloidal sol prepared from titanium iso-propoxide used as a starting material by applying the sol-gel method. It was characterized by particle size analyzer, XRD, FE-SEM, and BET analysis. The adsorption isotherms of dye molecule on $TiO_2$ films were obtained at three different temperatures (30, 45, $60^{\circ}C$) and at three different pH (3, 5, 7). The adsorption kinetics of dye molecule on $TiO_2$ films were obtained at three different temperatures (30, 45, $60^{\circ}C$. The adsorption experimental data were correlated with Langmuir isotherm model and pseudo-second-order model. Also the isosteric enthalpies of dye adsorption were calculated by the Clausius-Clapeyron equation. In addition, the adsorption energy distribution functions which describe heterogeneous characteristics of nanocrystalline $TiO_2$ film surface were calculated by using the generalized nonlinear regularization method. We found that efficient adsorption of N719 dye from aqueous solution onto $TiO_2$ films can be successfully achieved by dye adsorption conditions and morphology of $TiO_2$ films.