以硫醇螯合奈米金屬粒子低溫製備 具低阻抗之導電漿材料

Abstract

1.以低溫/金屬螯合技術製備導電銀漿材料 本研究主要探討傳統式與新穎式導電銀漿/墨水之差異。以往傳統導電銀漿材料存在銀奈米顆粒與非極性溶劑之間分散性不佳，或無法旋塗、浸塗及連續成型等難以解決的問題。因此，必須仰賴更多分散與黏著劑作為輔助以保持銀的原先導電能力，但同時也增加了製造成本。近年來，為了改善傳統式導電銀漿的缺點，我們實驗室致力開發新穎式導電銀漿；以及如何同時兼具分散性佳、可大尺度塗佈及降低成型溫度等優異條件。藉由低溫合成及金屬螯合技術，已成功製作銀/寡聚噻吩之導電複合材料；並由場發式電子顯微鏡可發現柱/片狀形貌結構呈現於此複材。自由電子可透過柱/片狀結構於連續傳導路徑上進行傳輸，並可維持低耗能型態，因此，藉由四點探針及電流-電壓量測證實銀/寡聚噻吩複材可展現優異的導電性質(薄膜導電率: 6.08 × 102 S/cm、塊材導電率: 1.80 × 104 S/cm)。此外，藉由金硫鍵螯合之行為可使銀/寡聚噻吩柱/片狀結構均勻分散於溶劑中，並且隨著噻吩單體當量濃度的改變亦可控制其長寬比(10:1)。X射線光電子儀譜則可佐證金硫鍵於銀/寡聚噻吩複材中成型。

2.以低溫/金屬螯合技術製備金屬氧化物/聚噻吩複合材料 透過低溫/金屬螯合之技術，本研究亦成功製備金屬氧化物/複合材料。金屬氧化物/聚噻吩複材具有優於原始氧化物及聚噻吩型態之導電度(複材: 10-5-10-4 S/cm，氧化鋅: 5.5 × 10-7 S/cm ，聚噻吩: 1 × 10-6 S/cm)，其源自於纖維狀結構的展現。纖維狀結構可提供連續性的傳輸路徑予電子，因此，電子可於此複材於低耗能的型態下進行傳遞。此外，因聚噻吩的自身特性及金硫鍵的作用，此複材可呈現特殊的磷光及光吸收性質。相較於水熱法或熱溶劑法下所製備之複材，以低溫成型之金屬氧化物/聚噻吩纖維材料具有凝膠型態，且可塗佈於玻璃基材上。

3.探討金屬螯合及共軛高分子量子點成型之行為 此部份，將專注於金屬離子與硫醇基團之間的螯合行為；透過紫外光-可見光及光致發光儀譜可證實聚(3-己烷噻吩)與銅離子於溶液中可形成發藍光性質之錯合物。藉由穿透式電子顯微鏡可發現聚(3-己烷噻吩)/銅/氯離子錯合物具有高分子量子點型態，且隨著結構尺寸及團聚現象的改變，其錯合物於溶液中可展現不同亮度及發光波段。另外，聚(3-己烷噻吩)/ 銅/氯離子錯合物可自組裝成柱及絲狀的結構，此現象可對應銀/寡聚噻吩及金屬氧化物/聚噻吩複材形貌之結果。 藉由金屬¬離子(銅、銀、鋅、鈦、鐵等)與硫醇之間的螯合作用，具優異導電性及分散性佳的導電漿料可成功製備。 同時可協助該製程除去因分散劑所造成之導電性質破壞的困擾。 透過金硫螯合的方式，導電漿料亦可於極性溶劑中製備以提高該材料的環保效益，及製程成本得以降低。

1. Preparation of conductive silver paste using hypothermia and chelating techniques In this study, the primary discussion would be focused on the difference between traditional and novel silver conductive pastes/inks. The unsolved problems include poor dispersion of silver nanoparticles in nonpolar solvent, difficult to form thin film via spin-coating and dip-coating. Therefore, it is important to increase the qualities of dispersants and binders of silver paste in organic solvent to get on conductivity properties of silver paste, but high cost of processing. Our group designed a novel conductive silver pastes with well dispersion, large-scale coating, and reducing molding temperature compared to traditional conductive silver paste. We have successfully fabricated the silver/oligothiophene conductive complexes through hypothermia synthesis and metallic cheleating techniques. Moreover, the rod/pellet morphologies can be observed in this complex by FE-SEM (Field Emission-Scanning Electron Microscopy). The conductivity of silver/oligothiophene complex displays a good conductive property using four-probe station and curve-voltage measurement (film conductivity: 6.08 × 102 S/cm, bulk conductivity: 1.80 × 104 S/cm) due to low energy consumption of rod/pellet structure. Furthermore, the rod/pellet structures of silver/oligothiophene complex can evenly be dispersed in solvent by metallic-thiol bond behavior, and the aspect ratio (10:1) of rod/pellet structure was controlled with change of thiophene monomer concentration. The formation of metallic-thiol bond was confirmed by X-ray photoelectron spectrum.

2. Synthesis of metal oxide/polythiophene complexes through hypothermia and chelating techniques We prepared the metal oxide/polythiophene complexes through simple and facile hypothermia and chelating techiques. The metal oxide/polythiophene complexes shows higher conductivity than that metal oxides and polythiophene (complex conductivity: 10-5-10-4 S/cm, zinc oxide conductivity: 5.5 × 10-7 S/cm, polythiophene conductivity: 1 × 10-6 S/cm) with fiber structures. The advantage of the fiber structure could supply the continuous route for electrons, and the electrons would be transmitted in the status of low energy consumption. Furthermore, these complexes displayed the specific luminescence and absorption properties based on photoluminescence and absorption results which attributed to metallic-thiol bond behavior and polythiophene character. Compared to the complexes synthesized by hydrothermal and solvent thermal methods, the fiber materials of metal oxide/polythiophene had colloid status, and it can be coated on glass substrates by hypothermia synthesis.

3. Studies of the behaviors with chelating and conjugated polymer dots formation In this part, it would be focus on the chelating within metal ion and thiol functional group; the poly(3-hexylthiophene) and cupric ions can be formed the coordination complex through metal-ligand interaction with blue luminescence proving by UV-visible and photoluminescence spectrums. TEM images revealed that Poly(3-hexylthiophene)/cupric/chloride ionic coordination complexes possess polymer-dot structures. Additionally, the coordination complex show different emission in solution state due to the different size and aggregation morphology. Furthermore, the poly(3-hexylthiophene)/cupric/chloride complexes were formed with rod and silk structures self-assembly correspond to the morphologic results of silver/oligothiophene and metal oxide/polythiophene complexes. Using the chelating within metallic ions (cupric, silver, zinc, titanium, ferric) and thiol can provide well dispersion and conductivity properties of conductive paste. It assists the fabrication to remove the harassment of conductivity broken derived from dispersants adjunction. The conductive paste can be easier prepared in polar solvent and the fabrication costs can be reduced through metal-thiol chelating approach for increasing of environmental efficiency.