Damasceno Daniela A, Rajapakse R K N D Nimal, Mesquita Euclides
School of Engineering Science, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
Department of Materials Physics and Mechanics, Institute of Physics, University of São Paulo, Ed. Van de Graaff-ed 10-Grupo SAMPA, Rua do Matão, Travessa R, 187, São Paulo 05508-090, Brazil.
Nanomaterials (Basel). 2020 Jul 21;10(7):1422. doi: 10.3390/nano10071422.
Cove-edged graphene nanoribbons (CGNR) are a class of nanoribbons with asymmetric edges composed of alternating hexagons and have remarkable electronic properties. Although CGNRs have attractive size-dependent electronic properties their mechanical properties have not been well understood. In practical applications, the mechanical properties such as tensile strength, ductility and fracture toughness play an important role, especially during device fabrication and operation. This work aims to fill a gap in the understanding of the mechanical behaviour of CGNRs by studying the edge and size effects on the mechanical response by using molecular dynamic simulations. Pristine graphene structures are rarely found in applications. Therefore, this study also examines the effects of topological defects on the mechanical behaviour of CGNR. Ductility and fracture patterns of CGNR with divacancy and topological defects are studied. The results reveal that the CGNR become stronger and slightly more ductile as the width increases in contrast to normal zigzag GNR. Furthermore, the mechanical response of defective CGNRs show complex dependency on the defect configuration and distribution, while the direction of the fracture propagation has a complex dependency on the defect configuration and position. The results also confirm the possibility of topological design of graphene to tailor properties through the manipulation of defect types, orientation, and density and defect networks.
Cove 边缘石墨烯纳米带（CGNR）是一类由交替六边形组成的具有不对称边缘的纳米带，具有显著的电子特性。尽管 CGNR 具有吸引人的尺寸依赖电子特性，但其机械性能尚未得到很好的理解。在实际应用中，诸如拉伸强度、延展性和断裂韧性等机械性能起着重要作用，尤其是在器件制造和运行过程中。这项工作旨在通过使用分子动力学模拟研究边缘和尺寸对机械响应的影响，来填补对 CGNR 机械行为理解上的空白。在应用中很少发现原始的石墨烯结构。因此，本研究还考察了拓扑缺陷对 CGNR 机械行为的影响。研究了具有双空位和拓扑缺陷的 CGNR 的延展性和断裂模式。结果表明，与普通锯齿形 GNR 相比，CGNR 随着宽度增加变得更强且延展性略有增加。此外，有缺陷的 CGNR 的机械响应显示出对缺陷构型和分布的复杂依赖性，而断裂传播方向对缺陷构型和位置具有复杂依赖性。结果还证实了通过操纵缺陷类型、取向、密度和缺陷网络来定制石墨烯性能的拓扑设计的可能性。
