Study On Cohesive Energy Of Two-dimensional Van Der Waals Heterostructure

Van der Waals(vd W)heterostructures formed by stacking two-dimensional materials are of excellent optical,electrical,thermal and magnetic properties,and thus can be widely used in semiconductor,photo catalysis,electrochemistry and other fields.So far,many works have been done on preparation and physical properties of van der Waals heterostructures,while mechanical properties such as interface energy measurement and regulation of interface property remain a challenge,which hinders the development of the novel structures.By using molecular dynamics simulation and theoretical modeling,the interfacial properties of van der Waals heterostructures are explored.Generally,we proposed two methods to measure the interfacial properties of heterostructures and one means to regulate the interfacial property.The main novelty lies in:(1)The cohesive energy of two-dimensional van der Waals heterostructures is measured by using shift loaded blister test,which is conducted by obtaining the relationship between loading force and debonding radius,as well as that between loading force and central deflection.The shift loaded blister test is found to be of feasibility.Furthermore,the influences of sample size,pre-fabricated hole shape,stacking sequence,and existing defects on the accuracy are explored.(2)The intercalation nanoparticle method is used to measure cohesive energy of van der Waals heterostructures.The theoretical basis of the method is well established.It is found that both the shape and size of nanoparticle have great influence on the results.What is more,the interfacial energy of van der Waals heterostructure can be given directly by introducing multiple nanoparticles of different size.(3)The interfacial properties of the hybridization graphene/Mo S₂ van der Waals heterostructure are studied,and the influence of the number,shape and aggregation of nanoparticles on the interfacial cohesive energy is revealed.It is found that the introduction of nanoparticles reduces the interfacial energy of graphene/Mo S₂heterostructures.The higher the agglomeration degree of nanoparticles,the weaker the interfacial energy is.And the interfacial cohesive energy of vd W heterostructure will increase by selecting suitable nanoparticles or nanosheets...