Optimization of preparation conditions for highly ordered structures of vapor-deposited organic thin films

高性能的有机薄膜需要对有机薄膜中分子的位置和取向进行三维（3D）调控。通过结合一维面外调节和二维面内对准，三维调节似乎是可行的。离面调控涉及作者首次论证的分子层外延方法，离面取向可以通过外电场诱导的界面各向异性、衬底晶体结构和衬底表面摩擦来控制。基于一种新的理论模型，从石英晶体微天平研究的角度探讨了这种特殊结构的形成机理。气相沉积技术可以产生具有垂直于衬底或横向于衬底的分子取向的有机薄膜，这取决于制备条件，例如衬底温度和沉积速率。不幸的是，其机制仍不清楚。在这项研究中，薄膜形成过程中的有机分子气相沉积已采用石英晶体微天平进行了研究。

Organic thin films with high performance require three-dimensional (3D) regulation of the position and the orientation of molecules in organic thin films. The 3D regulation appears to be feasible by combination of one-dimensional out-of-plane regulation and two-dimensional in-plane alignment. The out-of-plane regulation involves the molecular layer epitaxy method firstly demonstrated by the author, and the out-of-plane alignment can be controlled by the interfacial anisotropy induced by the external electric field, the substrate crystal structure and the rubbing of the substrate surface. The mechanism of the specific structure formation is discussed from the quartz crystal microbalance study on the basis of a novel theoretical model. The vapor deposition technique can produce organic thin films with a molecular orientation normal or lateral to the substrate, depending on the preparation condition, such as the substrate temperature and the deposition rate. Unfortunately, the mechanism is still unclear. In this study, thin film formation during vapor deposition of organic molecules has been investigated by using quartz crystal microbalance.