透明導電薄膜即是透明且可導電的薄膜，應用相當廣泛，包含觸控面板、太陽能電池、可撓性之LCD及OLED，導電高分子是新型透明導電薄膜的一種，以聚二氧乙基噻吩:聚苯乙烯磺酸化合物Poly(3,4-ethylenedioxythiophene): poly(styrene-4-sulfonate)，PEDOT:PSS為代表材料。本研究以簡易的製備方式，將電化學剝離石墨烯(Electrochemical exfoliated graphene，ECG)混合PEDOT:PSS製成複合薄膜，以探討添加石墨烯後的透明導電薄膜之光電特性。電化學剝離石墨烯製備過程不須複雜的化學變化，產率高且成本低。將電化學剝離之石墨烯摻雜在PEDOT:PSS中，PEDOT分子與石墨烯以π-π鍵鍵結，而PSS鏈與石墨烯的微量官能基鍵結，降低PEDOT與PSS間庫倫引力，使PEDOT與PSS分離且PEDOT產生構象變化，且石墨烯與PEDOT形成導電網絡，以利於導電，其片電阻由0.36 kΩ/□降至0.18 kΩ/□。PEDOT:PSS穩定性差，其透明導電薄膜放置約60天後無法測量到片電阻值，從不同天數量測之ATR-FTIR譜圖中可觀察到，C-H及O-H發生明顯變化。而PEDOT:PSS/ECG透明導電薄膜經270天依然可測量到片電阻值，且不同天數量測之ATR-FTIR譜圖之譜線無劇烈變化，故推測PEDOT:PSS中的C-H及O-H鍵結改變使整體結構不穩定導致裂化。PEDOT:PSS混合石墨烯不只可提升導電性，也可提升穩定度耐久性，本實驗將探討PEDOT:PSS劣化原因以及添加石墨烯後改善之處。;Transparent conductive films (TC films), which have good properties of optically transparent and electrically conductive, are widely used in touch screen, solar cell, flexible LCD and OLED. The conductive polymer is used as TC films, such as Poly(3,4-ethylenedioxythiophene): poly(styrene-4-sulfonate) (PEDOT:PSS). In this study, we used an easier method to mix the electrochemical exfoliated graphene (ECG) into PEDOT:PSS. The effects of graphene additives on optoelectronic properties of PEDOT:PSS were investigated. Electrochemical exfoliation method is widely applied due to high scalability and low production cost, especially it does not need complicatedly chemical reactions. We mixed the ECG powders into PEDOT:PSS. In this way, PEDOT molecular and ECG sheet were combined with π-π bond, and PSS chains bond on the functional group of ECG. These reactions decrease the Coulombic interaction between PEDOT and PSS, which induced phase separation and conformational change of PEDOT. It improved the conductivity of TC films so that the sheet resistance decreased from 0.36 kΩ/□ to 0.18 kΩ/□. In the electrical stability measurement, the sheet resistance of PEDOT:PSS TC films could not be measured after 60 days. The ATR-FTIR spectrum for PEDOT:PSS TC films were employed, where the C-H and O-H peaks were observed changed after 40 days. However, the sheet resistance of PEDOT:PSS/ECG can be measured after 270 days. The ATR-FTIR spectrum for PEDOT:PSS/ECG TC films showed no huge variation. We suppose that the changes of C-H and O-H are the key that makes PEDOT:PSS damaged. In conclusion, the effects of graphene additives promote the conductivity and stability of PEDOT:PSS.
