• Journal of IKEEE
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• v.25 no.1
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• pp.128-132
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• 2021

In this paper, the surface of electrodes used in solar cells was roughened using wet etching method among surface texturing method, and after surface treatment, dye sensitive solar cell using TiO2 oxide semiconductor was produced. The surface spectroscopic properties of surface treated electrodes were analyzed according to etching time, and by evaluating the electrical properties of TiO2 dye-sensitized solar cells produced according to etching time, the study on improving the efficiency of solar cells according to surface treatment was conducted. As a result, solar cells that etched the electrode surface for 10 minutes could see an improvement of about 27.46[%] over their existing efficiency.

• Analytical Science and Technology
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• v.9 no.1
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• pp.72-77
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• 1996

In the process of solar energy conversion into electrical energy using the photoelectrochemical cell containing the sensitizer, rose bengal and supersensitizer. $I^-$, the photocurrent is stabilized and durable. But the long time span of irradiation causes the decrease of photocurrent monotonically. Spectroscopic and electrochemical analyses of rose bengal solution containing $I^-$ revealed that the decrease of concentration of rose bengal was attributed to the reaction of rose bengal in the dark with $I_2$ formed as a result of the possible photocatalytic reaction of rose bengal with $I^-$.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.175-175
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• 2013

염료감응형 태양전지(Dye Sensitized Solar Cells; DSSC)에서 투명전극(Transparent Conducting Oxide; TCO)으로 사용되는 ITO, FTO의 경우 자원의 희소성과 고온에 취약하며 취성과 같은 단점 등이 있다. Graphene은 단원자층의 얇은 물질로써 우수한 전도도와 투과도, 고강도와 고탄성의 특성들을 가진다. 이러한 특성들을 가지는 Graphene을 기존의 투명전극을 대체하여 DSSC의 작업전극에 적용 하였다. 본 실험에서 사용된 그래핀 시트는 근적외선을 source로 하는 RTA (Rapid Thermal Annealing)장비에 탄화수소 기반의 gas를 주입하여 Ni위에 성장시켰으며, 습식방법인 용액Etching 방식을 사용하여 유리판 위에 전사시켰다. 전사된 Graphene 투명전극의 전기적 특성과 광학적 특성을 평가하기 위해 4 point probe, FT-IR, 마이크로 Raman분광법, 광학현미경 및 투과도를 측정하여 평가 하였다. 전사된 Graphene 투명전극을 염료감응형 태양전지 작업전극에 적용하여, DSSC소자를 제작하고, Solar Simulator로 광전변환효율 및 EIS(Electrochemical Impedance Spectroscopy)를 측정하여 기존의 FTO로 만든 DSSC와 비교하였다.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.600-605
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• 1990

Electron injection from excited rose bengal into the conduction band of a thin film of SnO$2$, semiconductor was investigated in an electrochemical cell, ITO/SnO$2$/rose bengal, NaClO$4$/Pt. It was observed that urea enhanced the supersensitized photocurrent, followed by the reduction in the photocurrent after a shallow maximum. Spectroscopic analyses of the dye solution containing urea revealed that dye aggregation appeared to be involved in the increased photocurrent, although the concentration of the dye was continuously decreased dye to photochemical reactions.

• Journal of the Korean Magnetics Society
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• v.25 no.5
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• pp.156-161
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• 2015

The electronic structures of the potential candidate semiconductor nanoparticles for dye-sensitized solar cell (DSSC), such as $ZnSnO_3$ and $Zn_2SnO_4$, have been investigated by employing X-ray photoemission spectroscopy (XPS). The measured X-ray diffraction patterns show that $ZnSnO_3$ and $Zn_2SnO_4$ samples have the single-phase ilmenite-type structure and the inverse spinel structure, respectively. The measured Zn 2p and Sn 3d core-level XPS spectra reveal that the valence states of Zn and Sn ions are divalent (Zn 2+) and tetravalent (Sn 4+), respectively, in both $ZnSnO_3$ and $Zn_2SnO_4$. On the other hand, the shallow core-level measurements show that the binding energies of Sn 4d and Zn 3d core levels in $ZnSnO_3$ are lower than those in $Zn_2SnO_4$. This work provides the information on the valence states of Zn and Sn ions and their chemical bonding in $ZnSnO_3$ and $Zn_2SnO_4$.

• Korean Journal of Optics and Photonics
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• v.34 no.5
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• pp.202-209
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• 2023

A KRISS-type small integrating sphere with a high spatial radiance uniformity was made using pressed polytetrafluoroethylene (PTFE) and a reflective rod to calibrate the spectral radiance responsivity of absolute radiant thermometers. The spatial radiance uniformity of the KRISS-type small integrating sphere was ±0.009%, five times higher than the best value reported by foreign national metrology institutions thus far. In addition, we improved the spatial radiance uniformity of a commercial sintered PTFE integrating sphere by a factor of 10.

• Journal of the Korean Chemical Society
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• v.64 no.2
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• pp.74-78
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• 2020

A push-pull conjugated dye (DCMP) was covalently immobilized on a silanized glass surface to produce a high sensitivity pH sensor film for operating in the acidic region. A pH-sensitive sensor film was prepared by photo-initiating copolymerization of a modified DCMP (DCMA), 2-hydroxyethyl methacrylate (HEMA) and triethylene glycol dimethacrylate on the silanized glass surface. The absorbance of the sensor film increased with increasing pH between pH 2.0 and 5.0, and the fluorescence intensity of the film also increased about 50 times with increasing pH in the same pH range. The sensor film was reversible and reproducible under acidic conditions. The sensor film showed a relatively short response time between 20-50 seconds and high selectivity for proton in the presence of various metal ions.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.47-52
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• 2012

Porous carbon nanofibers were prepared as a gas sensor electrode to study the $CO_2$ sensing property based on effects of porosity and introduced amine functional groups. Electrospun fibers were obtained by using electrospinning method with polyacrylonitrile precursor and they were treated by the thermal treatment and chemical activation. Amine functional groups were introduced by the liquid state treatment using diethylenetriamine. The specific surface area increased up to $2000m^2/g$ by the chemical activation. The Introduced amine functional group was identified using FT-IR spectroscopy. $CO_2$ gas sensing property was improved as four folds via introduced amine functional groups on the activated carbon nanofiber. In conclusion, the gas sensing property was improved based on the developed porosity by the chemical activation and the chemical attraction of $CO_2$ gas by introduced functional groups.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.177-181
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• 2012

Dye-sensitized solar cells(DSSCs) based on $TiO_2$ film photo anode incorporated with different amount of grapheme nanosheet(GNS) are fabricated and their photovoltaic performance are investigated. The $TiO_2$-GNS composite electrode has been prepared by a direct mixing method. The DSSC performance of this composite electrode was measured using N3 dye as a sensitizer. The performance of DSSCs using the $TiO_2$-GNS composite electrodes is dependent on the GNS loading in the electrodes. The results show that the DSSCs incorporating 0.01 wt% GNS in $TiO_2$photo anode demonstrates a maximum power conversion efficiency of 5.73%, 26% higher than that without GNS. The performance improvement is ascribed to increased N3 dye adsorption, the reduction of electron recombination and back transport reaction as well as enhancement of electron transport with the introduction of GNS. The presence of both $TiO_2$(anatase) and GNS has been confirmed by FieldEmission Scanning Electron Microscopy(FE-SEM). The decrease in recombination due to GNS in DSSCs has been investigated by the Electrochemical Impedance Spectroscopy.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.300-300
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• 2010

Thiourea가 염료감응 태양전지의 I-/I3- redox 전해질 내에서 additive로 사용될 때의 효과를 알아보았다. I-/I3- 가 존재하는 전해질에 thiourea를 첨가하게 되면, 전류는 40% 증가하고 전압은 9% 내려간다. 전류 증가로 인해 전체 효율은 23%의 증가분을 보인다. thiourea가 녹아있는 acetonitrile 용액은 pH가 10로 Bronsted base인데, I-/I3- 가 존재하는 전해질 용액에 thiourea를 넣으면, pH=3의 변화를 보인다. 이것은 thiourea와 iodine 사이의 반응에 의해 수소이온 농도가 증가했기 때문이다. 또한 UV-Vis 분광분석 결과 I3- 농도가 감소한 것을 확인하였으며, 이는 iodine이 thiourea 와 반응에 참여하여 소모되었기 때문에 상대적으로 I3- 농도가 감소한 것으로 해석할 수 있다. I3- 농도 감소로 인해 recombination 이 감소하여 voltage가 증가할 것으로 기대되었으나, I2와 thiourea의 반응으로 인해 생성된 proton 농도로 인해 TiO2 의 전도띠 에너지가 변화가 더 우세하게 일어나 결과적으로는 voltage가 감소한 것이다. 증가된 photocurrent 의 경우 역시, proton 농도 증가 및, iodide 농도 증가로 설명할 수 있었다.