Departamento de Física, ICEx , Universidade Federal de Minas Gerais , Avenida Presidente Antônio Carlos 6627 , Belo Horizonte CEP 31270-901 , Brazil.
Departamento de Física, ICEB , Universidade Federal de Ouro Preto , R. Diogo de Vasconcelos 122 , Ouro Preto CEP 35400-000 , Brazil.
Langmuir. 2018 Jun 12;34(23):6903-6911. doi: 10.1021/acs.langmuir.8b00506. Epub 2018 Jun 4.
The association of organic molecules with two-dimensional (2D) materials, creating hybrid systems with mutual influences, constitutes an important testbed for both basic science self-assembly studies and perspective applications. Following this concept, in this work, we show a rich phenomenology that is involved in the interaction of thionine with graphene, leading to a hybrid material formed by well-organized self-assembled structures atop graphene. This composite system is investigated by atomic force microscopy, electric transport measurements, Raman spectroscopy, and first principles calculations, which show (1) an interesting time evolution of thionine self-assembled structures atop graphene; (2) a highly oriented final molecular assembly (in accordance with the underlying graphene surface symmetry); and (3) a strong n-type doping effect introduced in graphene by thionine. The nature of the thionine-substrate interaction is further analyzed in experiments using mica as a polar substrate. The present results may help pave the way to achieve tailored 2D material hybrid devices via properly chosen molecular self-assembly processes.
有机分子与二维（2D）材料的结合，形成相互影响的混合系统，这是基础科学自组装研究和未来应用的重要试验台。基于这一概念，在这项工作中，我们展示了噻吩与石墨烯相互作用所涉及的丰富现象学，导致在石墨烯上形成由组织良好的自组装结构组成的混合材料。通过原子力显微镜、电输运测量、拉曼光谱和第一性原理计算对该复合体系进行了研究，结果表明：（1）在石墨烯上噻吩自组装结构的有趣的时间演化；（2）最终分子组装具有高度取向性（与底层石墨烯表面的对称性一致）；（3）噻吩在石墨烯中引入了强 n 型掺杂效应。通过将云母作为极性衬底进行实验，进一步分析了噻吩-衬底相互作用的性质。这些结果可能有助于通过适当选择分子自组装过程来实现定制的二维材料混合器件。
