Physicochemical and optical properties of nanosize titania based materials prepared by the sol-gel method = 졸-겔법에 의한 나노크기 티타니아계의 물성제어 및 광특성

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In order to study the variation of physicochemical properties of nanosize titania particles prepared according to some experimental variables, the hydrolysis-condensation reaction of titanium isopropoxide(TTIP) has been carried out by the sol-gel method. Isopropanol has been added into the reaction mixture as a diluting agent before reaction, and $HNO_3(H^+)$ has been used as a peptizing acid catalyst after reaction. The mole ratio of TTIP/isopropanol, $H^+$/TTIP, and $H_2O$/TTIP proved to be importent experimental variables affecting the primary particle size, morphology, and the crystalline phase. The kinds of metal alkoxide and acid catalyst have been changed to see their effects. Also, the effect of metal dopants with various ionic radius on the phase transition have been investigated. To enhance the crystallinity of titania particles and to obtain the uniform particle size distribution, the aged sol was hydrorhermally treated by changing the temperature at 160-240 ℃. Using the light scattering analyzer, XRD, Raman, Zeta meter, SEM/TEM, BET techniques, the titania particles were characterized. Also, a titania based solar cell was manufactured as an example of nano-particle application, and a correlation between the property of titania particles and the photoelectro-chemical performance of solar cell was investigated. As the $H^+$/TTIP mole ratio increased and the $H_2O$/TTIP mole ratio decreased, the aggregate and the primary particle size increased. Most of titania particles prepared at lower $H^+$/TTIP ratio below about 0.2 was of the anatase form with a trace of brookite phase. By the control of the $H^+$/TTIP ratio, the pure rutile phase could be prepared at room temperature. However, once the pure anatase phase was formed at the sol state, the phase transfor-mation to the rutile phase did not take place even by the hydrorhermal treatment at 240 ℃. In the case of rutile particles at the sol state, the morphology was changed from sphere and ellipse to ro...
Advisors
Park, Seung-BinMoon, Sang-Jin박성빈문상진
Description
한국과학기술원 : 화학공학과,
Publisher
한국과학기술원
Issue Date
1999
Identifier
150177/325007 / 000935187
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학공학과, 1999.2, [ xvi, 170 p. ]

Keywords

Room temperature; Phase transformation; 나노크기 티타니아; 졸-겔법; 상온; 상전이; Nanosize titania; Sol-gel method

URI
http://hdl.handle.net/10203/28794
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=150177&flag=dissertation
Appears in Collection
CBE-Theses_Ph.D.(박사논문)
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