Triplet Photophysics in Donor-Acceptor and pi-Conjugated Systems

凭借这一奖项，化学学部的大分子、超分子和纳米化学项目正在支持德克萨斯大学圣安东尼奥分校的Kirk Schanze教授研究光与有机和含金属的半导体分子和聚合物的相互作用，目的是了解它们吸收光能时发生的基本过程。一个关键的目标是了解电子自旋对材料性质的作用。电子自旋态很重要，因为它关系到分子与光的相互作用，因为它决定了发光二极管（led）和太阳能电池等应用的效率。铂、硒、碲等金属对电子自旋的影响也在研究中。该项目由一个包括本科生和研究生的小组执行，重点是代表不足的群体的参与。与沙特阿拉伯阿卜杜拉国王科技大学（KAUST）的一个小组进行了国际合作。该项目预计将产生广泛的影响，因为作为这些研究重点的有机半导体正被用于开发柔性发光设备和显示器、太阳能电池、传感器和射频ID标签中使用的塑料电子材料。因此，在这笔赠款下发展的基础科学可能对国家卫生、国防和安全部门的技术发展产生长期影响。该项目最初将涉及新的半导体有机、有机金属和聚合物材料的化学合成。其次，新材料的性能将通过各种技术来表征，包括测量它们的光吸收和光发射特性。具体来说，脉冲激光技术将用于了解这些新型半导体材料在吸收光时形成的中间激发态的时间演变。这些实验将在皮秒到微秒的时间尺度上进行。这些结果将在新的或现有的物理化学模型中进行解释，从而能够分配这些中间体的电子自旋态特征。这将允许定量结构-性质关系的发展，将分子和聚合物结构与系统如何与光能相互作用联系起来。计算化学将在特定情况下用于模拟材料的电子结构，这些信息将有助于解释实验结果。选定的材料将用于原型设备应用，包括有机太阳能电池和场效应晶体管配置，目的是将物理化学信息与材料设备性能联系起来。该研究的结果有望加强对供体-受体共轭系统光电特性的理解，特别关注三重态分子激发态在这种系统中所起的作用。

With this award, the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry is supporting Professor Kirk Schanze at the University of Texas at San Antonio to study the interaction of light with organic and metal-containing semiconducting molecules and polymers with the objective of understanding the fundamental processes that occur when they absorb light energy. A key goal is to understand the role played by electron spin on the properties of the materials. Electron spin state is important as it relates to the interaction of molecules with light because it determines the efficiency in applications such as light-emitting diodes (LEDs) and in solar cells. The effect of metals such as platinum, selenium, and tellurium on the electron spin is also being investigated. The project is being carried out by a team including undergraduate and graduate students with emphasis on participation by underrepresented groups. An international collaboration is included with a group at the King Abdulla University of Science and Technology (KAUST) in Saudi Arabia. The project is expected to have broad impact because the organic semiconductors that are the focus of these studies are being used to develop plastic electronic materials used in flexible light emitting devices and displays, solar cells, sensors and radio frequency ID tags. Thus, the basic science being developed under this grant may have long term implications in technology development for the national health, defense and security sectors.The project will initially involve the chemical synthesis of new semiconducting organic, organometallic and polymeric materials. Second, the properties of the new materials will be characterized by various techniques, including measurement of their light absorption and light emission characteristics. Specifically, pulsed laser techniques will used to understand the time evolution of the intermediate excited states that are formed upon light absorption by these new semiconducting materials. These experiments will be carried out on timescales ranging from picoseconds to microseconds. The results will be interpreted within new or existing physical chemical models, enabling the assignment of the electronic spin state characteristics of these intermediates. This should permit the development of quantitative structure-property relationships which relate the molecular and polymer structure to how the systems interact with light energy. Computational chemistry will be used in specific cases to model the electronic structure of the materials, and this information will aid in the interpretation of the experimental results. Select materials are to be used in prototype device applications, including organic solar cells and field-effect transistor configurations, with the objective of relating the physical chemical information to material device performance. The results of the study are expected to enhance understanding of the optoelectronic properties of donor-acceptor conjugated systems, with a particular focus on the role played by triplet molecular excited states in such systems.