Molecular Photonic Materials

在这个由化学部化学结构、动态和机制B项目资助的项目中，北卡罗来纳大学教堂山分校化学系的杰拉尔德·迈耶教授描述了锚定在金属氧化物表面的分子的分子间电子转移反应。本研究的目标是利用自交换反应作为在光电器件中应用的氧化物表面传输电荷的手段，即将太阳能转换为存储的化学能或电能（例如染料敏化太阳能电池）。该项目位于物理有机、无机和材料化学的界面，因此非常适合各级科学家的教育。这个群体也处于有利地位，可以为科学领域代表性不足的学生提供最高水平的教育和培训。北卡罗莱纳当地和农村的小学生拓展活动也是资助项目的一部分。研究表明，光氧化染料分子锚定在敏化介孔纳米晶（锐钛矿）TiO2薄膜上，通常用于染料敏化太阳能电池，可进行自交换分子间电子转移反应（称为跳空穴），其动力学和效率可在分子水平上调节。这些发现提供了在不损失吉布斯自由能的情况下将电荷传输到所需位置的机会。特别关注的是解决以下基本问题：如何调整分子结构来控制分子间的电子转移？流体溶液中的自交换反应与氧化物表面的自交换反应之间是否存在相关性？染料之间的自交换电子转移是否会影响不想要的复合反应？与含有两个（或更多）氧化还原活性基团的分子的自交换能被连接它们的桥控制吗？首次利用了一种动力学方法，使绝热/非绝热边界上的氧化还原平衡能够量化。期望的电子转移化学是由脉冲光激发或应用电位引发的，并通过原位光谱-电化学、吸收各向异性、计时吸收法和瞬态吸收光谱法进行量化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In this project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Gerald Meyer of the Department of Chemistry at the University of North Carolina at Chapel Hill is characterizing intermolecular electron transfer reactions for molecules anchored to metal oxide surfaces. The goal of this research is to exploit self-exchange reactions as a means to transport charge across oxide surfaces for applications in optoelectronic devices, namely for the conversion of solar energy into stored chemical energy or electricity (e.g. dye-sensitized solar cells). The project lies at the interface of physical organic, inorganic, and materials chemistry, and is therefore well suited to the education of scientists at all levels. This group is also well-positioned to provide the highest level of education and training for students underrepresented in science. Outreach activities to grade school students in local and rural North Carolina are also part of the funded project. Research has shown that photo-oxidized dye molecules anchored to the sensitized mesoporous nanocrystalline (anatase) TiO2 thin films commonly used for dye-sensitized solar cells undergo self-exchange intermolecular electron transfer reactions (termed hole-hopping) with dynamics and efficiencies that can be tuned at the molecular level. These findings provide an opportunity to transport charges to desired locations without a loss in Gibbs free energy. Particular focus wiis being given to address the following fundamental questions: How can molecular structure be tuned to control intermolecular electron transfer? Is there a correlation between self-exchange reactions in fluid solution and those on oxide surfaces? Does self-exchange electron transfer between dyes influenced unwanted recombination reactions? Can self-exchange with molecules that contain two (or more) redox active groups be controlled by the bridge that links them? A kinetic approach that enables redox equilibria at the adiabatic/non-adiabatic border to be quantified for the first time is being utilized. The desired electron transfer chemistry is being initiated by pulsed light excitation or with an applied potential and quantified by in situ spectro-electrochemistry, absorption anisotropy, chronoabsorptometry, and transient absorption spectroscopy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.