Reporter : Wan-Ting Chiou Adviser : Ming-Shyong Tsai Date : 2011/10/26 Fuorine-doped tin dioxide nanocrystals 製備FTO，並探討FTO的導電性。 Reporter : Wan-Ting Chiou Adviser : Ming-Shyong Tsai Date : 2011/10/26

Outline Introduction Materials and methods Conclusion ＊ Materials ＊ Characterization Conclusion

Outline Introduction Materials and methods Conclusion ＊ Materials ＊ Characterization Conclusion

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 氟參雜二氧化錫的晶格中，氟原子取代了氧的位子，釋放自由電子促進較高的導電率。參雜二氧化錫，由於有寬廣的波段間隙、在可見光範圍區具有高光學透射度、良好的(基板)附著力 ，所以有很多應用，例如：氣體感測器、太陽能轉化器、紅外線反射玻璃、防靜電塗料。

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 FTO具有很強的耐熱性 、附著玻璃力、化學穩定性。製造FTO有很多的方法，例如:噴霧裂解法、化學氣相沉積法、溶膠凝膠法、水熱法。 因為噴霧裂解法形成的薄膜需要在高溫450度C下做熱處理 ，化學氣相沉積法需要在高溫或者真空的條件下進行實驗，溶膠凝膠法則需要在空氣中550 °Ｃ熱處理獲得FTO奈米結晶。而水熱法只需要低的反應溫度，所以作者採用水熱法來進行實驗操作。

Outline Introduction Materials and methods ＊ Materials Conclusion ＊ Characterization Conclusion

Materials Tin tetrachloride Ammonium hydroxide Oxalic acid Ammonium fluoride Deionized water SnCl4 NH4OH氨水 草酸H2C2O4 NH4F 去離子水

Methods tin tetrachloride A green sol A green sol (dopping SnO2) Ultrasonic treament Deionized water A green sol (dopping SnO2) A green sol (undopped SnO2) SnCl4(ag) Hydrothermal treatment Aqueous ammonia adjust pH to 8 ammonium fluoride precipitated 6.67g四氯化錫溶於31ml去離子水，逐滴加入氨水調整到Ph值到8，形成沉澱物。將此沉澱物過濾後再以去離子水洗去表面不純物NH4+和Cl-離子，後來再添加2.68g的草酸至沉澱物中。此溶液回流4小時100度C，分成２杯，一杯添加氟化氨，一杯未添加氟化氨，以水熱法分別處理這2杯溶液後，形成綠色的溶膠後，用超音波震盪來分散，作比較。(放入100ml的高壓鍋持溫180度72小時) solution Reflux Filter and wash Oxalic acid

Characterization SnO2 sol (undopped NH4F) SnO2 sol (dopping NH4F) dry power power TEM Zeta potential 將添加氟化氨和未添加氟化氨分別作TEM、HRTEM(高解析透射光譜儀)、Zeta potential測量。將添加氟化氨和未添加氟化氨分別以80度乾燥後將所得的粉末作XRD、四點探針、XPS(X-ray光譜儀。 Four-probe XRD XPS

Outline Introduction Materials and methods Conclusion ＊ Materials ＊ Characterization Conclusion

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. 1水熱法是成功的備制FTO奈米結晶 2由XRD和TEM圖譜可得知晶粒大約為9~13nm 3由XPS可觀察到錫和氟原子的存在 4當氟和錫的莫耳比是2時,薄膜電阻值是最低的

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