| 摘要: | 本篇以文獻中的有機小分子2,6二苯基二?吩併[3,2-b:2',3'-d]?吩(2,6-diphenyldithieno[3,2-b:2',3'-d] thiophene
DP-DTT
化合物 1)出發，設計並開發出以三併環?吩(DTT)與雙三併環?吩(BDT)作為中心結構的2-五氟苯基-6-苯基二?吩併[3,2-b:2',3'-d]?吩(2-pentafluorophenyl-6-phenyldithieno[3,2-b:2',3'-d]thiophene
FPP-DTT
化合物2)、2,6-二苯基雙二?吩併[3,2-b:2',3'-d]?吩[2,6-diphenylbis(dithieno [3,2-b:2',3'-d]thiophene)
DP-BDT
化合物 3]、2-五氟苯基-6-苯基二?吩併[3,2-b:2',3'-d]?吩(2-pentafluoro phenyl-6-phenylbis(dithieno [3,2-b:2',3'-d]thiophene)
FPP-BDT
化合物4)，將此四種材料經由物理氣相沈積法(physical vapor transport, PVT)分別養成單晶，經由單晶繞射實驗解得其立體結構後，製備成單晶及薄膜場效電晶體元件。利用單晶場效電晶體元件討論晶體結構與分子內在(intrinsic)電荷傳輸性質的關係，同時探討與薄膜表面形貌對於電荷傳輸的影響。
化合物1與 化合物3的單晶結構為魚骨狀排列方式，結晶成片狀，化合物2與化合物4則為面對面排列，結晶成針狀，其中化合物2 存在著最短的分子間距離3.756?，其單晶場效電晶體元件電洞遷移率(hole mobility, ?)高達0.741cm2/V-s，開關電流比約為105，化合物 4電洞遷移率達0.725 cm2/V-s。化合物1與化合物3測得的最高載子遷移率分別為0.359 cm2/V-s、 0.405 cm2/V-s。
將以上四個有機小分子材料分別製成有機薄膜元件，在基板為25oC的條件下觀察薄膜表面形貌可發現化合物1在薄膜表面結晶性良好，為片狀結晶，載子遷移率可達0.202 cm2/V-s，化合物2製成元件表面形貌為長條狀結晶，載子遷移率可達0.134 cm2/V-s。另外也將蒸鍍基板升溫，觀察基板溫度對於薄膜表面晶粒大小提升與載子遷移率的影響。
Based on the reported core structure of dithieno[3,2-b:2',3'-d] thiophene (DTT), a series of organic semiconductor molecules was designed and synthesized, which are 2,6-diphenyldithieno[3,2-b:2',3'-d] thiophene (DP-DTT,compound1), 2-pentafluorophenyl-6-phenyl- dithieno[3,2-b:2',3'-d]thiophene(FPP-DTT, compound 2) 2,6-diphenyl- bis(dithieno [3,2-b:2',3'-d]thiophene (DP-BDT, compound 3), and 2-pentafluorophenyl-6-phenylbis(dithieno[3,2-b:2',3'-d]thiophene (FPP- BDT, compound 4). Single crystals for each compound were prepared by physical vapor transport (PVT) method in a home-made reactor, and were used for single crystal field-effect transistor (SCFET) devices fabrication in order to study their intrinsic charge transport behavior. Single crystals of compound 1 and compound 3 exhibit herring-bone structure, while compound 2 and compound 4 exhibit face-to-face π-π stacking. Among these, compound 2 exhibits the shortest intermolecular distance of 3.756?, and a highest hole mobility of 0.741 cm2/V-s for SCFET, as well as a high current on-off ratio of 105. The hole mobilities for SCFET of compound 4, compound 1, and compound 3 were 0.725 cm2/V-s, 0.359 cm2/V-s, and 0.405 cm2/V-s, respectively. Meanwhile, organic thin-film transistor (OTFT) devices for each compound were also prepared in order to explore the correlation between the thin-film morphology and charge carrier mobility. With vacuum thermal evaporation at ambient substrate temperature of 25oC, compound 1 showed good crystallinity with 2-dimentional film morphology, as well as a high mobility of 0.202 cm2/V-s. Compound 2 exhibited 1-dimentional crystal structure, and hole mobility of 0.134 cm2/V-s for the film transistor. Substrate temperature was also raised during the evaporation process in order to study the effect of temperature on film morphology. |
