高傳導性的自組裝超分子奈米結構

Abstract

在此論文中我們透過新穎的超分子概念利用具備生物識別氫鍵作用力的腺嘌呤(adenine)導入高分子聚（3-烷基噻吩）(P3HT)側鏈中，藉由腺嘌呤之間的物理網狀交聯形成一個具有高熱穩定性、抗溶劑腐蝕性、光學及電化學特性的共軛高分子(PAT)。我們更進一步的藉由不同溶劑的調控，利用其電洞傳輸特性與n-type材料PCBM{[6,6]-phenyl C61-butyric acid methyl ester, PCBM)}混摻，發現自組裝形成了奈米尺度且均勻分佈的殼核(in tetrachloroethane)及反殼核(in dimethyl sulfoxide)的球狀微胞。我們藉由DLS, AFM和TEM儀器確定了自組裝微胞及逆微胞的形成並且透過了UV-Vis, photoluminescene, XPS和拉曼光譜發現PAT能夠成功的將能量轉移至PCBM。透過CV電化學的分析，我們得知PAT的LUMO能階(-3.03eV)比起P3HT的LUMO能階(-3.25eV)可以與PCBM的LUMO能階形成更大能階差，所以更有效的防止電子回流。因此我們利用PAT/PCBM作為電子元件的傳導層發現其開路電壓(Voc)為0.54V、短路電流(Isc)達到229pA遠高於PCBM(Voc=0.32V和Isc=79.2pA)。PAT/PCBM為第一個利用超分子殼核自組裝微胞具備高傳導性質，提供未來高效率電子元件一個有潛力的發展方向。

Here we present a new concept to improve electronic performance of existed functional polymers by introduction of bio-complementary interaction. In this thesis, a new adenine-grafted poly(3-hexylthiophene) (PAT) has been prepared which exhibits high thermal stability, good solvent resistance, excellent optical and electrochemical properties in the solid state owing to the adenine induced physical cross-linking. We further fabricated hybrid nanoparticles of p-type PAT and n-type fullerene derivative {[6,6]-phenyl C61-butyric acid methyl ester, PCBM)} materials by solvent blending method. The resulting complexes self-assembled into micelles (in tetrachloroethane) and reverse micelles (in dimethyl sulfoxide) of nanoscale size and formed stable dispersions. The self-assembly phenomena were investigated by DLS, AFM and TEM provided further details into the mechanisms of evolution. Consequently, the results of UV-Vis, photoluminescene, XPS, and Raman spectrum also confirm that energy transfer from PAT to PCBM was successfully observed at the interface. Moreover, the highest occupied molecular orbital (HOMO) level of PAT is at -5.25 eV, which is close to PCBM (HOMO = -6.10 eV). In addition, because the lowest unoccupied molecular orbital (LUMO) level of PAT is at -3.03 ev, the energy barrier for electron-blocking ability is significantly increased relative to the commercial P3HT (LUMO = -3.25 eV). When the PAT/PCBM is utilized as a conducting layer in electronic device, the resulting device reaches an average open-circuit voltage (Voc) of 0.54 V and a short-circuit current (Isc) of 229 pA which are much higher than that of PCBM (Voc = 0.32 V and Isc = 79.2 pA). PAT/PCBM system is the first example of supramolecular micelle possessing high conducting capacity, providing a potential route towards next-generation, high-efficiency electronic device.