Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
J Am Chem Soc. 2011 Jul 6;133(26):10119-33. doi: 10.1021/ja200054z. Epub 2011 Jun 14.
The chemical compositions and structures of organic-inorganic interfaces in mesostructurally ordered conjugated polymer-titania nanocomposites are shown to have a predominant influence on their photovoltaic properties. Such interfaces can be controlled by using surfactant structure-directing agents (SDAs) with different architectures and molecular weights to promote contact between the highly hydrophobic electron-donating conjugated polymer species and hydrophilic electron-accepting titania frameworks. A combination of small-angle X-ray scattering (SAXS), scanning and transmission electron microscopy (SEM, TEM), and solid-state NMR spectroscopy yields insights on the compositions, structures, and distributions of inorganic and organic species within the materials over multiple length scales. Two-dimensional NMR analyses establish the molecular-level interactions between the different SDA blocks, the conjugated polymer, and the titania framework, which are correlated with steady-state and time-resolved photoluminescence measurements of the photoexcitation dynamics of the conjugated polymer and macroscopic photocurrent generation in photovoltaic devices. Molecular understanding of the compositions and chemical interactions at organic-inorganic interfaces are shown to enable the design, synthesis, and control of the photovoltaic properties of hybrid functional materials.
介孔有序共轭聚合物-二氧化钛纳米复合材料中有机-无机界面的化学组成和结构对其光电性能有显著影响。通过使用具有不同结构和分子量的表面活性剂结构导向剂（SDAs）来促进高疏水性供电子共轭聚合物与亲水性电子受体二氧化钛骨架之间的接触，可以控制这种界面。小角 X 射线散射（SAXS）、扫描和透射电子显微镜（SEM、TEM）以及固态 NMR 光谱的组合提供了对材料中无机和有机物种在多个长度尺度上的组成、结构和分布的深入了解。二维 NMR 分析确定了不同 SDA 嵌段、共轭聚合物和二氧化钛骨架之间的分子水平相互作用，这些相互作用与共轭聚合物的光激发动力学的稳态和时间分辨光致发光测量以及光伏器件中的宏观光电流产生相关。对有机-无机界面组成和化学相互作用的分子理解表明，可以设计、合成和控制混合功能材料的光电性能。
