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  • 學位論文

以噻吩和芴共軛系統之硬桿-軟鏈嵌段共聚物 於電子元件上的應用

Thiophene and Fluorene Based Conjugated Rod-Coil Block Copolymers for Electronic Device Applications

指導教授 : 陳文章

摘要


共軛硬桿-軟鏈嵌段共聚合物藉由分子設計的方法可調控電子元件性質已被廣泛應用於有機光電元件的裝置之上。嵌段共聚物的近期發展中,含電子施體與受體之高分子為被廣泛研究之項目同時硬桿-軟鏈嵌段聚合物也具有巨大潛力應用於可拉伸電子元件之中。因此,不同高分子結構對電以元件特性的影響是我們關心的問題。本論文探討了以下主題:(1)設計與合成新穎電子施體-受體共軛有機高分子材料(2)進行電晶體式與阻抗式的記憶體元件製備與測試(3)硬桿-軟鏈嵌段共聚合物之組成對於可拉伸電晶體元件效能的影響。以下總結了本論文的重要發現茲分述如下: 1. 利用簡易設計的電子施體(聚噻吩)-電子受體(聚側鏈異靛藍)嵌段共聚物應用於高效能場效電晶體式記憶體(第2章):主要探討電子施體(聚3-己基噻吩)(P3HT)-電子受體聚(聚懸掛側鏈異靛藍)(Piso)嵌段共聚物的合成,形態和電晶體式記憶元件特性。在本章節中,藉由 P3HT和具有不同分子量的Piso 利用點擊反應 (click reaction) 製備P3HT44-b-Pison(“n”表示聚合度; n = 10, 20, 60和100)嵌段共聚物。熱退火處理後展現納米纖絲結構的P3HT44-b-Piso10和P3HT44-b-Piso20有機場效電晶體(OFET)可分別具有4.56 × 10 -2 和2.02 × 10 -2(cm 2 / V s)的遷移率,其特性類似於高規整度P3HT均聚物之表現。更重要的是,在OFET存儲器元件中同時可用作電荷層和半導體層的P3HT44-b-Pison 隨著Piso的嵌段長度的增加,其存儲窗口由26 V擴增至79 V。此外所製備的非揮發性儲存元件還顯示出大於104級數的 ION/IOFF 比率,且有大於104 s的保留時間和大於100個循環的寫入-讀取-抹去-讀取(WRER)。 2. 使用帶有芴硬桿和側鏈異靛藍軟鏈的施體-受體嵌段共聚物應用於高性能可拉伸阻抗式記憶元件(第3章):雙嵌段共聚物由電子施體的聚[2,7-(9,9-二己基芴)](PF)硬桿經由點擊反應結合電子受體聚(聚懸掛側鏈異靛藍)(Piso)。 PF / Piso比例(PF14-b-Pison(n = 10, 20, 60和100))的變化顯著調節了聚合物電子性能和高分子鏈間排列。隨著Piso的長度增加,共聚合物的HOMO和LUMO能階會逐漸降低,進而影響PF和Piso域之間的電荷捕獲和分子內電荷轉移環境。利用三明治結構之ITO / PF14-b-Piso / Al元件構造研究了阻抗式記憶體元件特性。所製備共軛PF導電通道可呈現穩定的電阻切換行為,表現出揮發性隨機存取記憶元件(SRAM)(PF14-b-Piso10)和非揮發性記憶件(WORM)(PF14-b- Piso20, 60, 100) 呈現ION/IOFF 比率106和穩定的滯留時間104 s的特徵。更令人感興趣的是,利用此儲存記憶器單元製備在聚(二甲基矽氧烷)(PDMS)基板上可呈現拉伸數據存儲裝置。再進一步探討可靠性和可再現的電子元件特性,包括SRAM和WORM阻抗型記憶體,檢測在0〜50%的範圍內在所施加的拉伸應變下拉伸的器件。 3. 使用硬桿聚(3-己基噻吩)-軟鏈聚(丙烯酸丁酯)的高性能可拉伸電晶體元件(第4章):聚(3-己基噻吩)-嵌段-聚(丙烯酸丁酯)的合成,形態和場效電晶體應用,其中共軛半導體P3HT和軟鏈PBA嵌段的組合為可拉伸式電子元件應用的理想材料,因低Tg 的PBA鏈段可顯著影響機械性能藉由改變P3HT / PBA比率。藉由測量薄膜拉伸係數則發現隨著PBA軟鏈段的長度增加而提昇薄膜的延展性,由原先P3HT的拉伸係數0.93 GPa下降到0.19 GPa (P3HT-b-PBA12k)。P3HT-b-PBA薄膜可自組裝成纖維狀納米結構甚至在低P3HT組成下仍保持納米纖維的薄膜微結構。此嵌段共聚物的電晶體性能皆可以呈現高於10-2 cm 2 V-1 s-1的p型遷移率,表明良好的電荷傳輸能力。最重要的是,觀察到在特定的嵌段比例下(P3HT-b-PBA6k),在100%應變下棋FET特性仍可高於10-2 cm 2 V-1 s-1同時有穩定的輸出曲線和高的ION / IOFF比率其超過106。

並列摘要


Conjugated rod-coil type polymers have attracted a significant interest for organic electronic and optoelectronic devices due to their tunable electronic properties through molecular design. In the recent progress of block copolymer, donor-acceptor polymers have been explored in device characteristics and also rod-coil polymers have strong potential to develop stretchable type of electronic devices. Therefore, the effects of the different polymer structure on the memory characteristics are our concerned issues. In this thesis address and explore the following subjects: (1) design and synthesis of new donor-acceptor block copolymers, (2) preparation and characterization of the transistor and resistor memory devices, and (3) correlation of rod-coil block copolymer composition with stretchable transistor characteristics. The following summarize the important discovery of this thesis: 1. Donor-Acceptor Poly(3-hexylthiophene)-block-Pendent Poly(isoindigo) with Dual Roles of Charge Transporting and Storage layer for High-Performance Transistor-Type Memory Applications (Chapter 2): The synthesis, morphology, and transistor device characteristics of donor-acceptor rod-coil diblock copolymers of poly(3-hexylthiophene) (P3HT)-block-poly(pendent isoindigo-functionalized methacylate)(Piso). In the following, P3HT44-b-Pison (“n” represents the degree of polymerization; n = 10, 20, 60 and 100) block copolymers were prepared by the click reaction between the P3HT and the Pisons with varied molecular weight. The organic field-effect transistors (OFET) fabricated from P3HT44-b-Piso10 and P3HT44-b-Piso20 with the nanofibrillar structures could have the mobilities of 4.56 × 10-2 and 2.02 × 10-2 (cm2 / V s), respectively, similar to that of the regioregular P3HT. More importantly, P3HT44-b-Pison employed as both charge layer and semiconducting layer in OFET memory devices exhibited the memory window of 26 to 79 V as the block length of Piso increased. In addition, the fabricated nonvolatile memory devices also showed the ION/IOFF ratios larger than 104, the retention time greater than 104 s, and the write−read−erase−read (WRER) more than 100 cycles. 2. High Performance Stretchable Resistive Memories Using Donor-Acceptor Block Copolymers with Fluorene Rods and Pendent Isoindigo Coils (Chapter 3): Diblock copolymers consisted of electron-donating poly[2,7-(9,9-dihexylfluorene)] (PF) rod and electron-withdrawing poly(pendent isoindigo) (Piso) coil were designed and synthesized through click reaction. The variation of the PF/Piso ratio (PF14-b-Pison (n = 10, 20, 60 and 100)) significantly tuned the polymer electronic properties and interchain organizations. The HOMO and LUMO energy levels of the studied polymers were progressively level-downed as the length of Piso increased, affecting the charge trapping and intra-molecular charge transfer environment between PF and Piso domains. Resistive memory characteristics were explored with a sandwiched ITO/PF14-b-Pisons/Al device configuration. The facilitated conjugated PF conducting channels led to stable resistance switching behaviors, exhibiting volatile static random access memory (SRAM) (PF14-b-Piso10) and non-volatile write-once-read-many-times (WORM) (PF14-b-Piso20, 60, 100) characteristics with a large ION/IOFF ratio (106) and a stable retention time (104 s). More attractively, such memory cells were integrated on a soft poly(dimethylsiloxane) (PDMS) substrate to reveal stretchable data storage devices. Reliable and reproducible electrical characteristics, including SRAM- and WORM-type memories, could be explored as the device stretched under applied tensile strain in a range of 0 ~ 50 %. 3. High Performance Stretchable Transistor Using Rod-Coil poly(3-hexylthiophene)-block-poly(butyl acrylate) (Chapter 4): We report the synthesis, morphology, and field-effect transistor applications of poly (3-hexylthiophene)-block-poly(butyl acrylate) (P3HT-b-PBA)s, which combination of the semiconductor P3HT and coil PBA blocks could be ideal materials for stretchable electronics applications. The low Tg PBA segment could significantly affect the mechanical properties by varying the P3HT/PBA ratios. Monitoring the tensile modulus decreases with increasing length of PBA coil chains, from 0.93 GPa for P3HT to 0.19 GPa for P3HT-b-PBA12k. The P3HT-b-PBA thin films self-assembled into fibrillar-like nanostructures and maintained the edge-on orientation within nanofiber domain even at low P3HT component. The transistor performance of rod-coil block copolymers all showed high p-type mobility over 10-2 cm2 V-1 s-1, indicating good charge transporting ability. Most importantly, the specific block ratio (P3HT-b-PBA6k), the strain-dependent FET characteristics were observed higher than 10-2 cm2 V-1 s-1, good stability of output curves, and high ION/IOFF ratio over 106 even under 100% strain.

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