可溶性有機半導體分子之合成及其應用於有機薄膜電晶體

Synthesis and Characterization of Soluble Organic Semiconductors and Their Application on Field Effect Transistors

趙庭漢(Ting-Han Chao)

指導教授 ： 周大新

國立臺灣師範大學/理學院/化學系/博士(2012年)

摘要

可溶性處理有機半導體材料解決方案是一個有前途的方式，為大面積，低成本，可彎曲性的電子設備製造。最有前途的 p 型半導體五環素，它具有高的場效應遷移率由於其在固態結晶程度高。然而，同樣的屬性也使得它在有機溶劑中的溶解度低，所以它是相當困難經由可溶性處理的解決方案過程中製備。最近，我們實驗室已開發出五環素前驅物為新型單羰基橋橫跨一個苯環組成。固體薄膜可準備從這些可溶性前驅物旋轉塗佈，然後他們可以經由化學反應熱或光轉換至五環素。消除CO的活化能低，轉換成五環素的產量高。例如，五環素的定量轉換溫度在 130-150 ℃，或在 357-366 nm 的紫外線照射下。產品純度證實由核磁共振，X射線衍射，熱重分析儀，示差掃描熱量分析儀， 傅立葉轉換紅外線光譜儀和可見光光譜儀等。用這些材料製成的有機場效電晶體設備領域最高水準的場效應遷移率 〜0.01 cm2 V-1s-1 , 開/關比 105。使用五環素衍生物的單晶，如最高的場效應遷移率 0.47 cm2 V-1s-1 開/關比 105，可以得到更好的性能。此外，我們描述了一個高度可溶的五環素具有易制毒化學雙酯組和反向的 Diels-Alder 反應在210 ℃開始反應。場效應遷移率 0.38 cm2 V-1s-1 開/關比 106。Acenes的一維方向的苯環數量成長，會增強在下一代電子設備使用的潛力。因為已超過五苯的 acenes 發現是不穩定的，但是，它被普遍接受的，他們不會在正常情況下特別有用的材料。在這裡，我們設計 hexacene 晶體，採用物理氣相傳輸方法，可以從monoketone架橋的前驅物得到。這些晶體是在黑暗的環境條件下一段時間的長期穩定。在晶體中，分子被安排在人字形陣列，與五環素頗為相似。在有機場效電晶體的測試中，使用單晶的 hexacene 顯示了一場效應遷移率明顯比五環素要來的快。這一結果表明，這可能是有益的進一步探索其他更高 acenes 潛力。

關鍵字

有機薄膜電晶體 ； 有機場效電晶體 ； 有機半導體分子 ； 可溶性有機半導體分子 ； 可溶性前驅物

並列摘要

Solution-processed organic semiconductors are a promising way for the fabrication of electronics devices with large areas, low cost, and high flexibility. The most promising p-type semiconductor is pentacene, which has high field effect mobility due to its high degree of crystallinity in the solid state. However, the same property also renders it low solubility in organic solvent, so that it is rather difficult to prepare devices through solution processes. Recently, our laboratory has developed a new type of pentacene precursors which consists of a mono-carbonyl bridge across one of the benzene rings. Solid films can be prepared from these soluble precursors by spin-coating, and then they can be converted to pentacene through chemical reactions either thermally or photochemically. The activation energy for removing the CO was low, and the yield of pentacene was high. For example, quantitative conversion to pentacene is achieved by heating at 130-150 oC, or under a UV irradiation at 357-366 nm. The purity of products were confirmed by NMR, XRD, TGA, DSC, FT-IR and UV-Vis. The highest field effect mobility of OFETs devices made with these materials was measured to be ~ 0.01 cm2 V-1s-1 with on/off ratio 105. Better performances can be obtained by using the single crystals of pentacene derivatives, e.g., the highest charge mobility was 0.47 cm2 V-1 s-1 with on/off ratio 105. Moreover, we describe a one-step synthesis of a highly soluble pentacene precursor having diester groups and retro Diels-Alder reaction starting at 210 oC. The field effect mobility was 0.38 cm2 V-1 s-1 with on/off ratio 106. Acenes can be thought of as one-dimensional strips of graphene and they have the potential to be used in the next generation electronic devices. Because acenes larger than pentacene have been found to be unstable, however, it was generally accepted that they would not be particularly useful materials under normal conditions. Here we show that by using a physical vapour-transport method, platelet-shaped crystals of hexacene can be prepared from a monoketone precursor. These crystals are stable in the dark for a long period of time under ambient conditions. In the crystal, the molecules are arranged in herringbone arrays, quite similar to that observed for pentacene. A field-effect transistor made by using a single crystal of hexacene displayed a hole mobility significantly higher than that of pentacene. This result suggests that it might be instructive to further explore the potential of other higher acenes.

並列關鍵字

Organic Thin Film Transistors ； Organic Field Effect Transistors ； Organic Semiconductors ； Soluble Organic Semiconductors ； Soluble Precursor

參考文獻

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