論五元并苯雜環共軛分子之拉電子末端取代基對固態結構和有機場效電晶體元件表現的影響

Roles of electron-withdrawing end caps in the solid-state packing and OFET performance of penta-fused heteroacenes

邱冠婷(Guan-Ting Ciou)

指導教授 ： 王建隆

國立交通大學/理學院/應用化學系所/碩士(2019年)

摘要

本研究著重於探討雜環并苯的共軛分子體系中，分子的拉電子末端取代基對共軛分子之固態結構堆疊及其元件表現於有機場效電晶體 (Organic field-effect transistor, OFET) 中的影響。共軛分子材料由國立臺灣大學汪根欉老師實驗室提供，共有5種樣品，利用這些共軛核心相同但有一處官能基改變或對稱性不同的分子，觀察側鏈烷基相對位置改變、末端取代基不同所造成的變化。本研究主要利用本實驗室研發之PDMS輔助長晶法(PDMS-Assisted Crystallization, PAC) 生成晶體陣列，使用光學顯微鏡 (optical microscopy, OM) 觀察其晶體形貌；再將晶體陣列作成OFET，以元件量測真空腔體及電流電性分析系統量測其元件效能，結果以加入拉電子End caps基團具有最顯著的改善效果。為了研究共軛分子之固態結構，本研究利用國家同步輻射研究中心之掠角X光繞射技術 (Grazing incidence X-ray diffraction, GIXRD) 取得各分子之二維繞射圖譜，藉此觀察分子在基板上的固態結構排列取向性；另外我們也使用穿透式電子顯微鏡(Transmission Electron Microscopy, TEM) 進行實驗，並藉由電子繞射圖 (Electron diffraction, ED) 所提供的資訊進行分析，判斷固態結構中的晶粒尺寸與分子排列的有序程度。本研究希望透過分析共軛分子之排列，進而了解其固態結構對有機場效電晶體之元件效能的影響。亦可藉由研究這些不同的并苯雜環共軛之衍生物，來幫助化學家了解如何設計共軛分子才可以達到更高的元件載子遷移率。

關鍵字

并苯雜環 ； 有機場效電晶體 ； 固態結構 ； 元件載子遷移率

並列摘要

Solid-state structures of conjugated molecules play an important role in the field-effect transistor (FET) performances of the molecules. Penta-fused heteroacenes are useful building blocks for molecules used in optoelectronic devices. Here, a series of 5 heteroacene derivatives (Penta-fused heteroacenes: 4,5-Bis(2-ethylhexyl)-dithieno[2,3-d:2',3'-d']thieno[3,2-b:4,5-b']dipyrrole) were studied. The molecules were divided into three groups based on the chemical structures of their substituents. Crystal arrays of these derivatives were prepared by the PDMS-assisted crystallization (PAC) procedure. By analyzing the optical microscopy (OM) images, grazing incidence X-ray diffraction (GIXRD) patterns, Electron diffraction patterns (ED) and OFET performances of these derivatives, it was found that the different molecular symmetry and intermolecular interaction based on substituents can significantly affect the solid-state morphology and the OFET performances of the molecules.

並列關鍵字

conjugated molecules ； heteroacenes ； X-ray diffraction ； Electron diffraction ； solid-state structure ； OFET ； organic electronics

參考文獻

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