Chiou 1 Transmission Electron Microscopy of Mineralogy_070806
Reporter : Wan-Ting Chiou Adviser : Ming-Shyong Tsai Date : 2011/10/26 1 Fuorine-doped tin dioxide...
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Reporter : Wan-Ting Chiou Adviser : Ming-Shyong Tsai Date : 2011/10/26 1 Fuorine-doped tin dioxide nanocrystals
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Transcript of Reporter : Wan-Ting Chiou Adviser : Ming-Shyong Tsai Date : 2011/10/26 1 Fuorine-doped tin dioxide...
Reporter : Wan-Ting ChiouAdviser : Ming-Shyong Tsai
Date : 2011/10/26
1
Fuorine-doped tin dioxide nanocrystals
Outline Introduction Materials and methods ＊ Materials
＊ Methods
＊ Characterization
Conclusion
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Outline Introduction Materials and methods ＊ Materials
＊ Methods
＊ Characterization
Conclusion
3
Introduction
• Fluorine-doped tin dioxide (FTO), in which fluorine atoms replace the oxygen sites in the lattice creating free electrons to promote higher conductivity.
• The doped SnO2 , due to its wide band gap (3.67 eV), high optical transmittance in the visible range and good substrate adherence, has many potential applications such as
＊ gas sensors
＊ solar energy conversion
＊ infrared-reflecting glass
＊ antistatic coatings 4
Introduction
• FTO possesses extraordinary high temperature resistance, strong adhesion to glass and excellent chemical stability.
• Numerous techniques have been used to obtain fluorine doped SnO2 materials
＊ Spray pyrolysis method
＊ Chemical vapor deposition method (CVD)
＊ Sol–gel method
＊ Hydrothermal method
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Outline Introduction Materials and methods ＊ Materials
＊ Methods
＊ Characterization
Conclusion
6
Materials
• Tin tetrachloride
• Ammonium hydroxide
• Oxalic acid
• Ammonium fluoride
• Deionized water
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Methodstin tetrachloride
SnCl4(ag)
adjust pH to 8
precipitated
Deionized water
Filter and wash
Aqueous ammonia
Oxalic acid
A green sol(dopping
SnO2)
solution
ammonium fluoride
Reflux
Hydrothermal treatment
A green sol(undopped SnO2)
Ultrasonic treament
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Characterization
TEM
SnO2 sol(dopping NH4F)
SnO2 sol(undopped
NH4F)
power power
dry
XPS
Zeta potential
Four-probe
SnO2 sol(dopping NH4F)
SnO2 sol(undopped
NH4F)
XRD
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Outline Introduction Materials and methods ＊ Materials
＊ Methods
＊ Characterization
Conclusion
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Conclusion
• FTO nanocrystals were successfully prepared by hydrothermal treatment.
• The grain size of as-synthesized SnO2 is calculated to be 9–13 nm through XRD and TEM patterns.
• XPS analysis confirms the presence of Sn atoms and F atoms.
• When F/Sn molar ratios is 2, the value of sheet resistance is minimum.
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