Enhancing multi-functional capabilities of boron nitride nanosheets through defect engineering

In spite of the outstanding properties of boron nitride nanosheets (BNNSs), their applications may be limited due to counterproductive effect of the unavoidable defects in their structure. As such, tailoring the performance of these 2D nanostructures through defect engineering is of crucial importance. In this regard, we have probed the mechanical and thermal properties of defective BNNSs containing randomly distributed atomic vacancies and patterned point defects. For this purpose, molecular dynamic (MD) simulation is carried out to quantitatively explore the stress–strain response of the designed models under the uniaxial tensile loading. Additionally, thermal conductivity of the samples is examined by means of the non-equilibrium MD approach. The results indicate that only 2% of randomly distributed atomic vacancies would decrease both the Young modulus and thermal conductivity of BNNS by 13.7 and 44%, respectively. Furthermore, it is deduced that in addition to the defects content, their arrangement has also noticeable effects on the mechanical and thermal features of this 2D nanostructure. At the same defect content of 2.5%, it is shown that the presence of line defects transverse to the loading direction has the most damaging effect on the BNNS Young’s modulus (i.e., 19.1%). This reduction is found to be 16.9 and 9.3% for the cases having randomly distributed vacancies and defects oriented parallel to the axial direction, respectively. Similar trend is also reported for the thermal conductivity of the defected structures. Moreover, to address the synergistic effects of mono-atomic vacancies, mechanical response of the BNNS samples containing double vacancy with different distances is thoroughly examined. In comparison with graphene, BNNS demonstrates to be less influenced by the defects and, therefore, is a potential candidate in applications such as polymer-based composites and efficient thermal management. This work provides some guidelines on promoting the BNNS multi-functional capabilities thorough its defect engineering.