"以五氯化銻為氧化劑進行聚(3,4-乙烯基二氧噻吩)分子層沉積研究"

Abstract

本研究首次以五氯化銻作為氧化劑，藉由分子層沉積技術進行3,4-乙烯基二氧噻吩之氣相聚合以生長聚(3,4-乙烯基二氧噻吩)薄膜，並探討其製程及後處理對薄膜特性之影響。五氯化銻因具有高揮發性，相較其他低揮發性氧化劑更適合應用在低溫沉積技術中。研究結果顯示，在150℃和90℃溫度下分子層沉積之聚(3,4-乙烯基二氧噻吩)膜可分別獲得424和243S / cm的高導電率。我們探討沉積溫度和五氯化銻劑量對薄膜性質的影響，發現：（1）相比於90℃，在150℃沉積時五氯化銻的物理吸附量較低，使其對聚(3,4-乙烯基二氧噻吩)過氧化影響較小，同時單體的遷移率上升，因此薄膜的結晶度更高，並擁有更佳的導電率; （2）對於在150℃下大於 20毫托和在90℃下大於13毫托的五氯化銻劑量下，由於過量的五氯化銻物理吸附導致高分子鏈過度氧化並干擾其結晶，致使導電率降低。另外數種後處理，包含去離子水清洗、熱處理及以多種氣體進行氣相浸潤皆會使高分子的摻雜程度下降，並降低導電率。其可能原因為後處理過程中五氯化銻作為摻雜物被去除所致。

This work investigated the processing, post-processing, and properties of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films fabricated by molecular layer deposition (MLD) through vapor phase polymerization of ethylene dioxythiophene (EDOT) with SbCl5 as an oxidant for the first time, taking advantages of the high volatility of SbCl5 to realize low-temperature deposition. High conductivity of 424 and 243 S/cm was obtained from the MLD PEDOT film deposited at 150 and 90 °C, respectively. Effects of the deposition temperature and SbCl5 dose were as follows: (1) Compared with 90 °C, 150 °C reduced physisorbed SbCl5 while increasing the mobility of the depositing monomers, resulting in higher crystallinity and less over-oxidation by SbCl5 in the PEDOT film, which consequently showed higher conductivity; (2) For SbCl5 doses > 20 mTorr at 150 °C and >13 mTorr at 90 °C, the PEDOT film exhibited reduced conductivity due to excessive physisorbed SbCl5 causing over-oxidation and interfering with the crystallization of PEDOT. Post-processing treatments—including thermal annealing under vacuum, rinse with water, and vapor phase infiltration (VPI) with several precursors—to the PEDOT films decreased the conductivity, likely due to their removal of the residual SbCl5 serving as dopants.