Simple 프로세스로 제조된 TiO2 페이스트를 이용한 염료감응 태양전지의 전기화학적 특성

Xing Guan Zhao,박주영,구할본 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.11

In this work, in order to manufacture the photoelectrode of dye-sensitized solar cells, thedifferent anatase TiO2 paste was prepared by simple route using hydrothermal method. In comparisonwith the traditional preparing process, the hydrothermally synthesized TiO2 gel was used to make pastedirectly. Thus, the making process was simplified and the solar conversion efficiency was improved. Incomparison with 5.34% solar energy efficiency of HP-1 photoelectrode, the 6.23% efficiency of HDP-1electrode was improved by 16.67%. This is because hydrothermally synthesized TiO2 gel was used tomake paste directly, the dispersibility between TiO2 particles was improved and get the smoothernetwork, leading to the charge transport ability of the electron generated in dye molecular was improved. Further, HDP-2 photoelectrode delivered the best results with Voc (open circuit voltage), Jsc (shortcircuit current density) FF (fill factor) and η(solar conversion efficiency) were 0.695 V, 15.81 mA cm-2,61.48% and 6.80%, respectively. In comparison with 5.34% of HP-1 photoelectrode, it was improved by27.34%. 본 실험에서는 수열합성법을 통하여 순수한 아나타제 TiO2를 제조부터 TiO2 페이스트 제조하기까지의 공정을 간소화하였다. 기존의 제조공정에 비해 수열합성한 TiO2 졸을 직접 페이스트화 시키는 공정은 많이 간소화되었고, 이를 염료감응 태양전지 광전극에 적용한 결과, 광전변환 효율을 향상시켰다. HP-1 전극 효율 5.34%에 비해 HDP-1 전극의 경우 6.23%로 16.67% 향상되었다. 이는 TiO2 졸을 직접 페이스트화 시킴으로써 TiO2 입자 간의 분산 특성을 향상시키고 원활한 네트워크로 인해 염료분자에서 생성된 전자들의 전하수송 능력이 향상되었기 때문이다. 또한, HDP-2 전극의 경우 Voc, Jsc, FF 및 η은 각각 0.695 V, 15.81 mA cm-2, 61.48% 및 6.80%로 가장 높았으며 HP-1 전극 5.34%에 비해 27.34% 향상되었다.

Addition of Electrospun TiO₂Nanofibers for Improving the Charge Capabilities of Polymer Electrolyte-Based DSSCs

Guan Zhao, Xing,Park, Ju-Young,Gu, Hal-Bon The Electrochemical Society 2014 Journal of the Electrochemical Society Vol.161 No.9

Tuning the Interfacial Area and Porosity of TiO₂ Film for Enhanced Light Harvesting in DSSC

Zhao, Xing Guan,Park, Ju-Young,Jin, En Mei,Gu, Hal-Bon The Electrochemical Society 2015 Journal of the Electrochemical Society Vol.162 No.1

<P>Pyrene is used as the template material in the preparation of porosity in TiO<SUB>2</SUB> films. Pores are created in the TiO<SUB>2</SUB> film, using a range of pyrene amounts (0, 2, 3, 4 wt%), to increase the light harvesting efficiency and electron charge capabilities at the TiO<SUB>2</SUB> film/dye/electrolyte interface. The specific surface area of the TiO<SUB>2</SUB> film increases from 49.2 to 115.8 m<SUP>2</SUP> g<SUP>−1</SUP> as the porosity are created with 3% pyrene added TiO<SUB>2</SUB> film (TiO<SUB>2</SUB>-pyrene-3). The pore volume of TiO<SUB>2</SUB>-pyrene-3 is 0.35 cm<SUP>3</SUP> g<SUP>−1</SUP>. The charge transfer of TiO<SUB>2</SUB>-pyrene-3 based dye-sensitized solar cell (DSSC) is faster than the other TiO<SUB>2</SUB> films. For TiO<SUB>2</SUB>-pyrene-3, the electron transport time is 4.19 ms and the electron recombination time is 34.82 ms. The diffusion coefficient is 8.36 × 10<SUP>−5</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP> for TiO<SUB>2</SUB>-pyrene-0 and increases to 1.39 × 10<SUP>−4</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP> for TiO<SUB>2</SUB>-pyrene-3. TiO<SUB>2</SUB>-pyrene-3 has the highest solar conversion efficiency of 7.58%, an increase of 11.47% over that of TiO<SUB>2</SUB>-pyrene-0, 6.80%.</P>

Preparation and Thermal Performance of Fullerene-Based Lead Salt

Guan, Hui-Juan,Peng, Ru-Fang,Jin, Bo,Liang, Hua,Zhao, Feng-Qi,Bu, Xing-Bing,Han, Wen-Jing,Chu, Shi-Jin Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.8

$C_{60}$ is widely investigated because of its unique structure. But its applications in solid propellant seem to be relatively neglected. $C_{60}$ has more outstanding features than carbon black which is widely used as a catalyst ingredient of solid propellant. To combine the advantages of fullerene and lead salts, another good composite in propellant catalysts, we synthesized a kind of fullerene phenylalanine lead salt (FPL) and explored its thermal performances by differential thermal analysis (DTA) and thermogravimetry analysis (TGA). The results show it undergoes four exothermic processes started from 408 K. Combined TGA and X-ray diffractometer (XRD), the decomposition mechanism of FPL was derived by TG-IR and comparing IR spectra of FPL and its residues after burned to $327^{\circ}C$, $376^{\circ}C$ and $424^{\circ}C$, respectively. Effect of FPL on the decomposition characteristic of hexogen (RDX), a type of explosive in propellant, has been investigated using DTA at different heating rate, which shows the decomposition temperatures of the explosive are all reduced by more than 20 K. The corresponding activation energy ($E_a$) is decreased by $30kJ{\cdot}mol^{-1}$. So FPL has potential application as a combustion catalyst in solid propellant.

Preparation and Thermal Performance of Fullerene-Based Lead Salt

Hui-Juan Guan,Rufang Peng,Bo Jin,Hua Liang,Fengqi Zhao,Xing-Bing Bu,Wen-Jing Han,Shijin Chu 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.8

C60 is widely investigated because of its unique structure. But its applications in solid propellant seem to be relatively neglected. C60 has more outstanding features than carbon black which is widely used as a catalyst ingredient of solid propellant. To combine the advantages of fullerene and lead salts, another good composite in propellant catalysts, we synthesized a kind of fullerene phenylalanine lead salt (FPL) and explored its thermal performances by differential thermal analysis (DTA) and thermogravimetry analysis (TGA). The results show it undergoes four exothermic processes started from 408 K. Combined TGA and X-ray diffractometer (XRD), the decomposition mechanism of FPL was derived by TG-IR and comparing IR spectra of FPL and its residues after burned to 327 °C, 376 °C and 424 °C, respectively. Effect of FPL on the decomposition characteristic of hexogen (RDX), a type of explosive in propellant, has been investigated using DTA at different heating rate, which shows the decomposition temperatures of the explosive are all reduced by more than 20 K. The corresponding activation energy (Ea) is decreased by 30 kJ·mol−1. So FPL has potential application as a combustion catalyst in solid propellant.

수열합성한 TiO2 분말을 이용한 염료감응형 태양전지의 전기화학적 특성

나병희,구할본,Xing Guan Zhao 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.1

In this work, according to temperature and time of hydrothermal synthesis, the electrochemicalproperties of TiO2 particle using TTIP based on changing temperature and time in the hydrothermal synthesiswere analyzed and optimized temperature and time were derived. When hydrothermal synthesis temperatureand time were 200℃ and 1 h, respectively. The fabricated DSSC delivered the best electrochemical properties. In that case, TiO2 particle size was 13.08 nm, electron transport time was 2.34×10-3 s and recombination timewas 4.01×10-2 s. The lowest impedance of 13.52 Ω and Voc, Jsc, FF is 0.70 V, 11.50 mAcm-2, 65.62%,respectively and corresponding efficiency of 5.34% was considered as the optimal. 본 실험에서는 TTIP를 이용한 TiO2 분말의 수열합성 온도와 시간에 따른 전기화학적 특성에 대하여 분석하였으며 최적화된 온도와 시간을 도출하였다. 수열합성 온도와 시간은 각각 200 ℃, 1시간의 경우 제작된 염료감응형 태양전지는 가장 우수한 전기화학적 특성을 나타내었다. 이때 TiO2 분말의 입자크기는 13.08 nm였다. 전자전달시간은 2.34×10-3 s, 재결합시간은 4.01×10-2 s였다. 임피던스는 13.52 Ω으로 가장 작았고 Voc, Jsc 및 FF은 각각 0.70 V, 11.50 mA cm-2 및 65.62%이며 이때 광전변환효율은 5.34%로 가장 높았다.

Electrochemical properties of metal salts polymer electrolyte for DSSC

구할본(Gu, Hal-Bon),Zhao, Xing Guan,Jin, En Mei 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

Dye-sensitized solar cell(DSSC) have been considered one of the promising alternatives to conventional solar cells, because of their low cost, easy fabrication and relatively high energy conversion efficiency. However, although the cell offers reasonable efficiency at least 11%, the use of a liquid electrolyte placed technological challenges for achieving the desired durability and operational stability of the cell. In order to prevent or reduce electrolyte leakage considerable efforts have been made, such as p-type semiconductor or organic hole-transport material that better mechanical properties and simple fabrication processes. In this work, we synthesized solid-state electrolyte containing LiI and KI metal salt with starting materials of poly ethylene oxide to substitute liquid electrolyte enhance the ionic conductivity and solar conversion efficiency. Li+ leads to faster diffusion and higher efficiency and K+ leading to higher ionic conductivity. The efficiency of poly ethylene oxide/LiI system electrolyte is 1.47% and poly ethylene oxide/potassium electrolyte is 1.21%. An efficiency of 3.24% is achieved using solid-state electrolyte containing LiI and KI concentrations. The increased solar conversion efficiency is attributed to decreased crystallinity in the polymer that leads to enhanced charge transfer.

Impact of UV curing process on mechanical properties and dimensional accuracies of digital light processing 3D printed objects

Lee, Younghun,Lee, Sungho,Zhao, Xing Guan,Lee, Dongoh,Kim, Taemin,Jung, Hoeryong,Kim, Namsu Techno-Press 2018 Smart Structures and Systems, An International Jou Vol.22 No.2

In the last decade, there has been an exponential increase of scientific interest in smart additive manufacturing (AM) technology. Among the different AM techniques, one of the most commonly applied processes is digital light processing (DLP). DLP uses a digital projector screen to flash an ultraviolet light which cures photopolymer resins. The resin is cured to form a solid to produce parts with precise high dimensional accuracy. During the curing process, there are several process parameters that need to be optimized. Among these, the exposure time affects the quality of the 3D printed specimen such as mechanical strength and dimensional accuracy. This study examines optimal exposure times and their impact on printed part. It was found that there is optimal exposure time for printed part to have appropriate mechanical strength and accurate dimensions. The gel fraction and TGA test results confirmed that the improvement of mechanical properties with the increasing UV exposure time was due to the increase of crosslinked network formation with UV exposure time in acrylic resins. In addition, gel fraction and thermogravimetric analysis were employed to microscopically investigate how this process parameter impacts mechanical performance.

Impact of UV curing process on mechanical properties and dimensional accuracies of digital light processing 3D printed objects

Younghun Lee,Sungho Lee,Xing Guan Zhao,Dongoh Lee,Taemin Kim,정회룡,Namsu Kim 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.22 No.2

In the last decade, there has been an exponential increase of scientific interest in smart additive manufacturing (AM) technology. Among the different AM techniques, one of the most commonly applied processes is digital light processing (DLP). DLP uses a digital projector screen to flash an ultraviolet light which cures photopolymer resins. The resin is cured to form a solid to produce parts with precise high dimensional accuracy. During the curing process, there are several process parameters that need to be optimized. Among these, the exposure time affects the quality of the 3D printed specimen such as mechanical strength and dimensional accuracy. This study examines optimal exposure times and their impact on printed part. It was found that there is optimal exposure time for printed part to have appropriate mechanical strength and accurate dimensions. The gel fraction and TGA test results confirmed that the improvement of mechanical properties with the increasing UV exposure time was due to the increase of crosslinked network formation with UV exposure time in acrylic resins. In addition, gel fraction and thermogravimetric analysis were employed to microscopically investigate how this process parameter impacts mechanical performance.

A study on left ventricular hypertrophy, QTc dispersion and hemodynamic differences in GXT according to excessive endurance exercise

( Piao Shun-zhe ),( Jin Zhong-xuan ),( Wang Guan ),( Zhao Ze-lin ),( Mu Yi-gang ),( Wen Jian-fei ),( Wang Xing ),( Il Su Kwon ),( Young Nam Cha ),( Young Ju Kim ) 대한운동사협회 2020 대한운동사협회 운동사대회자료집 Vol.2020 No.-