Wang Zi, Chang Hao, Wang Tong, Wang Haibo, Yan Donghang
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, 130022, P. R. China.
J Phys Chem B. 2014 Apr 17;118(15):4212-9. doi: 10.1021/jp412310y. Epub 2014 Apr 9.
The heterostructure, a basic active unit applied in the device level, plays an important role in traditional inorganic optoelectronics. In the organic field, although the requirement for the heterostructure is crucial, achievement and understanding on the growth and functionality of organic heterostructure are still finite, especially for ordered crystalline organic multilayers with smooth interfaces. Here a series of highly ordered crystalline heterostructures with molecule-level smoothness were obtained from single layer to alternate multilayer with a phthalocyanine molecule and a perylene derivative. Well-defined epitaxy relationship and crystal alignment were evidenced from the atomic force microscopy (AFM), X-ray diffraction (XRD), and transmission electron microscope (TEM) results. The evolution of the films reveals that, for organic-organic alternate multilayer growth, along with the intrinsic properties of organic molecules such as the packing and preferred growth direction, the soft matter properties of organic films contribute to well-defined heteroepitaxy despite that the lattice mismatch between the two materials' bulk phases is large. Thin film phases of the first few layers benefit the grain coalescence and thus the formation of smooth films. Potential application is implied from the heterojunctions' good transport ability.
异质结构作为应用于器件层面的基本活性单元，在传统无机光电子学中发挥着重要作用。在有机领域，尽管对异质结构的要求至关重要，但对有机异质结构的生长和功能的认识与成果仍然有限，尤其是对于具有光滑界面的有序结晶有机多层膜而言。在此，通过酞菁分子和苝衍生物，从单层到交替多层获得了一系列具有分子水平光滑度的高度有序结晶异质结构。原子力显微镜（AFM）、X射线衍射（XRD）和透射电子显微镜（TEM）结果证明了明确的外延关系和晶体取向。薄膜的演变表明，对于有机-有机交替多层生长，除了有机分子的固有性质（如堆积和择优生长方向）外，尽管两种材料的体相之间晶格失配较大，但有机薄膜的软物质性质有助于形成明确的异质外延。前几层的薄膜相有利于晶粒聚结，从而形成光滑薄膜。异质结良好的传输能力暗示了其潜在应用。
