Department of Physics and Department of Chemistry, Liaoning University, Shenyang, 110036, P.R. China.
Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface Science, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing, 100083, P.R. China.
Sci Rep. 2017 Mar 24;7(1):417. doi: 10.1038/s41598-017-00542-9.
The mechanisms of the weak interactions within hybrid materials such as quantum dot (QD) and graphene (GR) have important implications for the design of related optoelectronic devices. We characterize the weak interactions in hybrid QD-GR systems using a non-covalent interactions approach. For a single CdSe QD with a core-cage structure, the intensity of the steric repulsive strain in every Cd-Se spatial four-atom ring of the cage surface is stronger than that of the inter-core-cage structure. Van der Waals (vdW) interactions occur within the cavity of the cage and within the six-atom rings of the cage surface. The spatial repulsion strain and attractive interactions play a key role in stabilizing the structure of the monolayer graphene. Interestingly, the spatial six-atom ring of the single QD change into spatial four-atom rings of the QD in the hybrid system, accompanied by the translation of vdW interactions into steric repulsive interactions. We conclude that the vdW interactions with π extensions and the weak attractive interactions within local areas between the QD and graphene together stabilize the integral structure of the hybrid QD-GR system. These results explain of the formation mechanism and the stabilization of the components in QD-GR hybrid materials.
杂化材料（如量子点（QD）和石墨烯（GR））中弱相互作用的机制对相关光电设备的设计具有重要意义。我们使用非共价相互作用方法来描述杂化 QD-GR 系统中的弱相互作用。对于具有核壳结构的单个 CdSe QD，壳表面每个 Cd-Se 空间四原子环中的空间位阻应变的强度强于核壳间结构。范德华（vdW）相互作用发生在笼腔和笼表面六原子环内。空间排斥应变和吸引力在稳定单层石墨烯的结构中起着关键作用。有趣的是，在杂化体系中，单个 QD 的空间六原子环变成了 QD 的空间四原子环，同时 vdW 相互作用转变为空间位阻应变。我们得出结论，vdW 相互作用具有π延伸性，QD 和石墨烯之间局部区域的弱相互作用共同稳定了杂化 QD-GR 系统的整体结构。这些结果解释了 QD-GR 杂化材料中组分的形成机制和稳定性。
