Controlling Solid State Structures of Conjugated Polymers: Optoelectronic and Transport Effects

共轭分子是薄膜晶体管（TFT）和有机发光二极管（OLED）的重要组成部分。 它们在这些器件中的性能特征主要取决于它们的固态结构和形态，而固态结构和形态又取决于它们的分子结构。 在本计画中，将以预期的方式合成共轭低聚物及分子堆积物。 分子性质，例如电离势、电子亲合势、极化率等，将通过使用赋予所需特性的组分结构合成共聚物或“共聚低聚物”来进行微调。 X射线晶体学和光谱学的结合将用于确定分子堆积及其对新材料光电性能的影响。 对于TFT，最佳填充基序具有以紧密间隔的（3.5A）堆叠排列的分子，其中堆叠方向的轴与电流流动的方向共线。 将使用Langmuir-Blodgett技术来排列基板（电极）表面上的功能化分子，并将确定分子结构和固态包装对传输性能的影响。 这些新材料将具有明确的固态结构，可以在平板显示器、“智能卡”、环境传感器以及涉及共轭聚合物和有机固体的相关应用中提供更好的性能。

Conjugated molecules are promising components of thin film transistors (TFTs) and organic light-emitting diodes (OLEDs). Their performance characteristics in these devices are critically dependent on their solid state structure and morphology which, in turn, depends on their molecular structure. In this project, conjugated oligomers and molecular packing in a predicted manner will be synthesized. Molecular properties, e.g. ionization potential, electron affinity, polarizability, etc., will be fine tuned by synthesizing co-polymers or "co-oligomers" using component structures that impart the desired characteristics. A combination of X-ray crystallography and spectroscopy will be used to determine the molecular packing and its effect on the optoelectronic properties of the new materials. For TFTs, the optimum packing motif has the molecules arranged in closely spaced (3.5A) -stacks with the axis of the stacking direction collinear with the direction of current flow. Langmuir-Blodgett techniques will be used to align the functionalized molecules on substrate (electrode) surfaces, and effects of molecular structure and solid state packing on the transport properties will be determined. These new materials will have well defined solid state structures that may give better performance in flat panel displays, "smart cards", environmental sensors, and related applications involving conjugated polymers and organic solids.