标题: 含共轭吡啶质子受体悬挂基氢键侧链高分子之超分子组装于有机光电材料之应用
Supramolecular Assembly of H-Bonded Side-Chain Polymers Containing Conjugated Pyridyl H-Acceptor Pendants for Organic Electro-Optical Materials Applications
作者: 梁宗琦
林宏洲
Lin, Hong-Cheu
材料科学与工程学系
关键字: 超分子;侧链高分子;液晶;发光;发光骤息效应;有机太阳能电池;Supramolecular;Side-Chain Polymers;Liquid Crystal;Fluorescence;Fluorescence Quenching Effects;Organic Solar Cell
公开日期: 2008
摘要: 本论文研究方向为探讨一系列包含共轭吡啶质子受体氢键侧链高分子之合成,利用超分子组装的特性,在三大方向在有机光电材料为研究主轴。
第一个部份,成功的聚合出以Sonogashira coupling 和Wittig-Horner反应合成出的两种发光吡啶单体,进而将发光高分子与不同的质子予体错合形成超分子侧链与交联高分子错合物,而此氢键高分子错合物之液晶及发光性质可以被吡啶共轭段及不同质子予体所调整。然而,含有较小pKa 值的质子予体可以让氢键高分子错合物得到红位移的发光。
第二个部份,成功的将吡啶单体与苯酸同分异构物(即,para-、meta-、和ortho-)共聚出液晶及发光氢键高分子。藉由FTIR、DSC、XRD鉴定其氢键的形成。此外,此氢键高分子与其错合物之液晶及发光性质不但与氢键效应有关,也被共聚不同位置的苯酸同分异构物所影响。接着,结合不同改质的奈米金球(酸或无酸改质),随着加入的奈米金球浓度变化,自身氢键(含有吡啶与酸)与无自身氢键高分子(含有吡啶与酸保护)的奈米复合材料,其PL发光强度将有不同程度的骤息。进一步,利用TEM观察自身氢键与无自身氢键高分子混合改质奈米金球,而其微观现象和PL骤息程度相互呼应,解释了自身氢键高分子的酸与改质金球的酸相互竞争所造成。
第三个部份,描述两种不同吡啶基比例系列的发光高分子超分子奈米复合材料,即,侧面甲基高分子和侧面甲氧基高分子,进而与质子予体的奈米粒子发展出可区分的聚集现象在TEM影像里。质子受体高分子不但显示了高程度聚集,而且可以使质子予体的奈米粒子均匀分散。并且,酸表面改质的奈米金球与侧面甲氧基的高分子之间的氢键作用力,比起无酸表面改质的奈米金球更有效的影响了发光骤息的现象。此外,与侧面甲基高分子比起来,侧面甲氧基高分子更容易的捕捉酸表面改质的奈米金球在超分子组装的奈米复合材料里。吡啶基质子受体高分子与质子予体的奈米粒子的氢键作用力可以解释相似的发光骤息效应。我们以实验数据建立了在不同的吡啶基高分子的指数方程式,进而可以预测Stern-Volmer常数。发展了多种奈米复合材料包含两种发光高分子(甲氧基和甲基高分子)与表面改质的奈米金球(酸和无酸改质),进而展示出差异性的聚集现象在TEM影像。未来我们可以基于奈米金球发光骤息的回复性,在化学感测与生医感测研究领域作进一步的发展。
最后一个部份,氢键侧链高分子与染料型质子予体结合(含末端氰酸基)。氢键高分子错合物得到了从440至462 nm宽广的吸收能带,且其光学能隙大约在2.11-2.25 eV之间。结果发现,在AM 1.5G、100 mW/cm2的模拟太阳光下,将合成出之氢键高分子错合物与PCBM([6,6]-phenyl C61-butyric acid methyl ester)混合为主动层材料,成功地以1:1 w/w的混合比例得到一具有短路电流3.17 mA/cm2、开路电压0.47 V、填充因子34%及最高之光电转换效率0.50%之有机太阳能电池。
First, two H-bonded acceptor polymers and were successfully prepared by polymerization of fluorescent pyridyl monomers, which were synthesized via Sonogashira coupling and Wittig-Horner reactions. Supramolecular side-chain and cross-linking polymers (i.e., H-bonded polymer complexes) were obtained by complexation of light-emitting H-acceptor polymers with various proton donor (H-donor) acids. Mesogenic and photoluminescent (PL) properties of light-emitting H-acceptor polymers can be adjusted not only by the central structures of the conjugated pyridyl cores but also by their surrounding non-fluorescent H-donor acids. Redder shifts of PL emissions in H-bonded polymer complexes occurred when the light-emitting H-acceptor polymers were complexed with H-donors having smaller pKa values.
Second, a series of PL and liquid crystalline (LC) self-H-bonded side-chain copolymers consisting of pyridyl H-acceptors and isomeric acid H-donors (i.e., para-, meta-, and ortho-benzoic acids) were synthesized. Supramolecular H-bonded complexes were also obtained by mixing the photoluminescent H-acceptor homopolymer with isomeric H-donor homopolymers. The formation of H-bonds was confirmed by FTIR, DSC, and XRD measurements. Moreover, PL and LC properties of the H-bonded copolymers and complexes were affected not only by the H-bonding effect of the supramolecular structures but also by the acid-substituted positions of isomeric H-donors. In combination with different functionalized gold nanoparticles (which bear acid or acid-free surfactants), the emission intensities of nanocomposites containing self-H-bonded copolymer (bearing both H-acceptor and H-donor moieties) and non-self-H-bonded copolymer (bearing acid-protected moieties), respectively, were quenched to different extents by varying the concentration of gold nanoparticles. The copolymeric H-acceptors and surface-modified gold nanoparticles demonstrated diverse morphological and PL quenching effects on the supramolecular architectures of nanocomposites, which result from competition between the H-donors from the acid pendants on copolymers and the acid surfactants on gold nanoparticles.
Third, this approach is exploring hydrogen-bonded (H-bonded) suparmolecular assembled behavior via both TEM and fluorescence quenching studies through organic solvent dissolving and evaporating processes. Different lateral methyl- and methoxy-substituted groups with pyridyl terminus of fluorescent side-chain polymers, it performed that the H-bonded interactions affect the fluorescence quenching effectively upon the addition of surface-modified gold nanoparticles bearing acid and acid-free surfactants in the fluorescence titrations experiments. We demonstrated that homopolymer PBOT1 has the highest Ksv constant in the compared fluorescent side-chain polymers. In addition, we established the exponential equation to predict Stern-Volmer constant in various pyridyl units of polymers from the experimental information. TEM studies displayed that interesting H-bonded suparmolecular behavior of addition into the carboxylic acid units of surface-modified gold nanoparticles. It is clearly observed that homogeneously gold nanoparticles distributions are on the fluorescent side-chain polymers. Thus, the TEM morphologies of H-bonded architectures demonstrate the versatility of the self-assembled processes in supramolecular nanocomposites of H-acceptor polymers and surface-modified gold nanoparticles.
Finally, novel supramolecular side-chain polymers were constructed by complexation of H-acceptor polymers, i.e., side-chain conjugated polymers containing pyridyl pendants, with low-band-gap H-donor dyes (bearing terminal cyanoacrylic acids) in a proper molar ratio. H-bonded polymer complexes exhibited broad absorption peaks in the range of 440-462 nm with optical band-gaps of 2.11-2.25 eV. The PSC device containing H-bonded polymer complex blended with PCBM (1:1 w/w) gave the best preliminary result with an overall power conversion efficiency (PCE) of 0.50%, a short-circuit current of 3.17 mA/cm2, an open-circuit voltage of 0.47 V, and a fill factor of 34%.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT009318831
http://hdl.handle.net/11536/78914
显示于类别:Thesis


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