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Fuorine-doped tin dioxide nanocrystals
Reporter : Wan-Ting Chiou
Adviser : Ming-Shyong Tsai
Date : 2011/10/26
1
Outline


Introduction
Materials and methods
＊ Materials
＊Methods
＊ Characterization

Conclusion
2
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
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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
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Materials
• Tin tetrachloride
• Ammonium hydroxide
• Oxalic acid
• Ammonium fluoride
• Deionized water
7
Methods
tin tetrachloride
Ultrasonic treament
Deionized water
SnCl4(ag)
A green sol
(dopping SnO2)
Aqueous ammonia
adjust pH to 8
precipitated
A green sol
(undopped SnO2)
Hydrothermal
treatment
ammonium
fluoride
solution
Reflux
Filter and wash
Oxalic acid
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Characterization
SnO2 sol
SnO2 sol
SnO2 sol
(dopping NH4F) (undopped NH4F) (dopping NH4F)
SnO2 sol
(undopped
NH4F)
dry
power
TEM
power
Zeta
potential
Fourprobe
XRD
XPS
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Outline


Introduction
Materials and methods
＊ Materials
＊Methods
＊ Characterization

Conclusion
10
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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