Synthesis and Properties of Mesostructured Thin Films

本课题研究了以表面活性剂和嵌段共聚物为结构导向剂的金属氧化物介观结构薄膜的制备和性能。一个中心概念涉及化学上不同的和空间上分离的介观结构区域。在分子水平上，介观结构由两个不同的区域组成：由溶胶-凝胶金属氧化物形成的“骨架”区域和由模板形成的“有机”区域。该项目包含两个相辅相成的目标。第一个目标是故意在透明的介观结构二氧化硅的特定区域放置掺杂剂。特定分子的位置将通过光学光谱来表征，多个掺杂之间的空间关系将通过能量转移来探测。第二个目标是在介观结构薄膜中合成半导体骨架并表征其形成过程。将合成二氧化锡的介观结构薄膜，并将使用光学探针来监测和解释胶束和金属氧化物骨架形成的动力学。要使用的光学方法提供在几厘米的胶片尺寸上在几秒的时间帧内发生的动态变换的50 nm分辨率。这些实验旨在确定从溶解的“单分子”(单个溶解的共聚分子)到胶束再到介观结构金属氧化物薄膜的演化。这些动态测量将关联薄膜沉积时发生的化学变化和结构发展。第二组实验将监测半导体框架的发展。将测量和解释介观结构薄膜中的电子传输。%制造具有独特电学和光学性能的介观结构薄膜的前景。这些新材料的发展将对光学物理领域和医疗应用传感器(例如植入物和体内和体外生物传感器)等器件领域产生重大影响。在这些领域接受培训的学生将在就业市场上竞争非常有利。这个项目将由化学部和材料研究部共同资助。

This project concerns the synthesis and properties of mesostructured thin films of metal oxides based on surfactant and block copolymers as the structure-directing agents. A central concept involves the chemically different and spatially separated regions of the mesostructure. On the molecular level, the mesostructures consist of two distinct regions: the "framework" that is formed by the sol-gel metal oxide, and the "organic" region that is formed by the template. The project contains two complementary objectives. The first objective is to deliberately place dopants in specified regions of transparent mesostructured silica. The location of specific molecules will be characterized by optical spectroscopy, and the spatial relationships between multiple dopants will be probed by energy transfer. The second objective is to synthesize semiconductor frameworks in mesostructured films and to characterize their formation processes. Mesostructured films of tin dioxide will be synthesized and optical probes will be used to monitor and interpret the dynamics of both micelle and metal oxide framework formation. The optical methods to be used provide 50 nm resolution of the dynamic transformations taking place in a time frame of a few seconds over film dimensions of several centimeters. The experiments are directed at determining the evolution that occurs from the dissolved "unimer" (individual dissolved copolymer molecules) to the micelle to the mesostructured metal oxide film. These dynamic measurements will correlate the chemical changes and structural development occurring as the film is deposited. The second set of experiments will monitor the development of the semiconductor framework. Electron transport in mesostructured films will be measured and interpreted. %%%The prospects for creating mesostructured films with unique electrical and optical properties. The development of these novel materials will have a significant impact on the fields of optical physics, and device areas such as sensors for medical applicatons (e.g., implants and in vivo and in vitro biosensors). Students trained in these areas will compete very favorably in the job market. This project is to be funded jointly by the Chemistry Division and the Division of Materials Research.