• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.97-102
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• 2004

용액 중에서 나노입자의 전기영동 특성을 이용한 전자종이용 잉크 제조를 위해 $TiO_2$ 나노입자를 저유전율 용매인 cyclohexane에 혼합한 후 용매와 용질의 비중차를 줄이기 위해 분말 상 polyethylen을 첨가하여 high energy milling의 방법으로 입자분쇄와 동시에 입자 표면에 고분자 풍을 코팅하였다. 용액내의 입자 분산성 향상과 용매 착색을 위하여 계면활성제와 oil-blue N을 첨가한 후 전자종이용 잉크를 제조하여 측정한 제타 전위 결과 cyclohexane 내에서 $TiO_2$의 제타전위는 -40mV 정도였으나 polyethylene으로 코팅한 후 계면활성제를 첨가하였을 경우 최대 -110mV 이상의 높은 값을 나타내었다. 실제 디스플레이 특성을 평가하기 위해 포토리소그래피를 이용하여 3인치 크기의 ITO glass 위에 $10{\mu}m$의 크기를 갖는 십자형의 격벽을 $40{\mu}m$의 높이로 균일하게 형성한 후 합성된 전자잉크로 주입하여 상부전극과 하부전극사이에 UV 경화제를 도포하여 UV 접합을 실시하였다. 격벽 내에서 입자의 mobility를 측정하여 환산된 전자잉크의 응답속도는 0.1cm/sec로 측정되었으나, 전기영동시 입자들의 움직임에 따른 반사광의 파형을 측정한 경우 0.07cm/sec의 응답속도를 나타내었다.

• Korean Journal of Optics and Photonics
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• v.29 no.5
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• pp.215-219
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• 2018

In this paper we show that the localized surface-plasmon resonance of Ag nanoparticles produced by laser dewetting can be effectively utilized for improving the photocurrent and efficiency of a dye-sensitized $TiO_2$ solar cell. An Ag thin film deposited on a conducting glass substrate was dewetted into nanoparticles by a pulsed laser. A dye-sensitized $TiO_2$ solar cell fabricated on this substrate containing the Ag nanoparticles exhibited improved photovoltaic performance, compared to a reference cell. This is attributed to the increased light trapping that arises from the localized surface-plasmon resonance of the dewetted Ag nanoparticles.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1097-1103
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• 2001

TiO$_2$anchored on a porous clay ceramic support (PCS) for use in lightweight photocatalyst were synthesized by the dropping precipitant method. A PCS of macro and micro pore size of around several mm~${\mu}{\textrm}{m}$ in diameter were prepared by the rapid heat treatment at, 1,15$0^{\circ}C$ for 10 min from low grade of clay. The change in pH of reaction solution due to the different addition rate of NH$_4$HCO$_3$as a precipitant, the reaction temperature and the concentration of TiCl$_4$had a pronounced effect on the nature of precipitated TiO$_2$particles on the surface of a PCS and the crystal structure of precipitated TiO$_2$particles. At an addition rate of 0.8 ml/min of NH$_4$HCO$_3$and pH=6 of reaction solution, homogeneous precipitation of TiO$_2$particles on a PCS was achieved. TiO$_2$particles with anatase phase was precipitated on the surface of a PCS at the low concentration of TiCl$_4$, the high addition rate of NH$_4$HCO$_3$and the high reaction temperature.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.401-402
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• 2003

TiO$_2$는 광촉매로서 자외선이 조사되면 여기상태로 되어 광활성을 나타내므로, 휘발성 유기화합물(VOCs), 악취, 중금속 물질 등을 제어하는데 널리 사용되고 있다(Lee and Biswas, 1998). TiO$_2$는 기상 및 액상 등 여러 가지 방법으로 제조되고 있는데(Morooka et al., 1989), 본 연구에서는 기상 방법의 하나인 전기가열 튜브로를 이용하여 TiOs 입자를 제조하였다. 즉, TTIP(titanium isopropoxide, Ti[OCH($CH_3$)$_2$]$_4$)와 공기를 전기가열 튜브로의 d열원을 이용하여 반응시키는 방법을 사용하였다. TiO2의 광활성에 영향을 미치는 변수로는 전기로의 온도, TTIP의 초기 농도, carrier gas의 유량, 산화시키기 위한 산소의 양, 수분의 양 등이 있다. (중략)

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.71-74
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• 2019

In this study, we fabricated two standard and inverted quantum dot light emitting diodes (QLEDs) using $TiO_2$ nanoparticles (NPs) with lower electron mobility than ZnO NPs as inorganic electron transport layer to suppress electron injection into the emitting layer. Current density was much higher for the inverted QLEDs than the standard ones. The inverted QLEDs were brighter, but showed low current efficiency due to the high current density. In addition, as the current density was higher, the driving voltage was higher, and the red shift was confirmed in the emission wavelength spectrum. The low current density in the standard structured devices showed that the possibility that $TiO_2$ NPs could suppress the electron injection in the QLEDs.

• Environmental Analysis Health and Toxicology
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• v.24 no.4
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• pp.333-339
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• 2009

In this study, we investigated the biological toxicity of nano-scale Zn (0.1, 0.5, and 1 mol%)-doped $TiO_2$ and pure $TiO_2$ nanoparticles using zebrafish embryogenesis as our model organism. Zn-doped $TiO_2$ nanoparticles were prepared using a conventional hydrothermal method for the insertion of zinc into the $TiO_2$ framework. The characters of Zn-doped $TiO_2$ (0.1%, 0.5%, 1%Zn) and pure $TiO_2$ were about 7~8 nm. These sizes were smaller than 100~200 nm of $TiO_2$ was prepared using the sol-gel method. Particularly, in this study, we found no significant biological toxicity in the hatching rate and abnormal rate under expose pure $TiO_2$ and Zn-doped $TiO_2$ nanoparticles were prepared using a conventional hydrothermal method of zebrafish. It was different from the biological damage under $TiO_2$ nanoparticles were prepared using sol-gel method. We assessed that the damage was not linked to the particle's nanometer size, but rather due to the prepare method. Moreover, $TiO_2$ nanoparticles were prepared using a hydrothermal method were not shown to cause cytotoxic effects, like apoptosis and necrosis, that are the major markers of toxicity in organisms exposed to nanomaterials. Therefore, there is some relationship with biological toxicity of nanoparticles and the prepare method of nanometer size particles.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.69-70
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• 2023

The development of advanced 3D printing technologies has opened up new opportunities for customized digital designs in the construction industry. Using nano- and micro-scale additives is expected to improve the performance of cement-based materials in 3D printing. TiO₂ particles have been widely used as reinforcing additives in cement-based materials. Therefore, this study aims to investigate the application of cement-based materials containing multi-size TiO₂ particles in binder jet 3D printing and the effect of different-size TiO₂ particles on the performance of printed samples. TiO₂ particles exhibit an excellent filling effect, which increases the density of the printed samples and promotes hydration, thereby improving the compressive strength of the samples. In addition, larger TiO₂ particles exert more pronounced filling and photocatalytic effects on the resulting samples.

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.301-307
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• 1997

Monodisperse, spherical $SiO_2/TiO_2$ composite fine powders were prepared by modified Sol-Gel process which $TiO_2$ fine Powders was used as a seed particles for condensation of TEOS (Tetraethyl Orthosilicate). The reaction was carried out under $N_2$ atmosphere at ambient temperature using $NH_3$ as a catalyst. Ethanol was used as a solvent. Drying process was carried out with vacuum trap which cooled by liquid $N_2$. The reaction variables were the concentration of TEOS, the concentration of ammonia, the size of $TiO_2$ seed and molar ratio of $SiO_2/TiO_2$. The optimum condition for the preparation of $SiO_2/TiO_2$ composite fine powders without agglomeration was [TEOS]=0.3M, [$NH_3$]=0.7M, size of $SiO_2/TiO_2$ seed = 200~300nm.

• Particle and aerosol research
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• v.6 no.4
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• pp.165-172
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• 2010

Titania is widely used as an effective photocatalyst for the photodegradation of environmental pollutants in air. In this study, novel N-doped $ZrO_2/TiO_2$ photocatalysts were synthesized via sol-gel method and characterized by UV-Vis spectrophotometer, transmission electron microscope, and X-ray diffractometer. N-doped $ZrO_2/TiO_2$ photocatalysts were nano-sized with an average particle size of about 20 nm. The XRD pattern of N-doped $ZrO_2/TiO_2$ photocatalysts showed both anatase and rutile phases. The photocatalytic activity of N-doped $ZrO_2/TiO_2$ photocatalysts was evaluated by degradation of NO under UV and visible light irradiation at various parameters such as amount of photocatalyst, concentration of NO, and intensity of light. The photocatalytic activity of N-doped $ZrO_2/TiO_2$ photocatalysts was effective for the enhancement of the degradation of NO and higher than that of $TiO_2$ photocatlysts under UV and visible light irradiation.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1152-1153
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• 2008

본 연구에서는 Ketjen black을 이용한 DSCs (Dye-sensitized solar cells)용 다공질의 $TiO_2$ nano-powder 제작기술을 제안한다. $TiO_2$ powder는 sol-gel법에 의해 Ti-isopropoxide와 2-propanol을 사용하여 제작되었으며, Ketjen black의 함량(0g$\sim$2g)을 달리하여 제작된 $TiO_2$ nano-powder의 다공성과 입자의 크기, 결정성등의 특성을 고찰하였다. 또한 이러한 $TiO_2$ powder를 paste로 만들어 다른 열처리 온도($100^{\circ}C{\sim}600^{\circ}C$)에서 $TiO_2$ 박막을 이용한 DSCs를 제작한 후 그 효율을 측정하였다. 그 결과 Ketjen black 1g을 함유시켜 만들어진 $TiO_2$ powder의 다공성과 입자 크기가 가장 우수한 것으로 FE-SEM의 측정결과 나타났으며, 500$^{\circ}C$의 열처리 공정을 거쳐 제작된 셀의 효율이 가장 높은 효율인 5.46%를 나타내고 있음을 확인할 수 있었다.