Effect of grafted amine groups on in-plane tensile properties and high temperature structural stability of borophene nanoribbons

The effects of grafted amine groups on in-plane tensile properties and structural stability of armchair and zigzag borophene nanoribbons (ABNRs and ZBNRs) are investigated by using molecular dynamics. The results show that the Young's moduli for the ABNR and ZBNR are 1.093 TPa and 0.978 TPa, respectively. Their ultimate elastic strains are respectively about 15.30% and 22.03%, showing distinct ductile and brittle fractures. When the BNRs are grafted with amine groups (-NH₂), the moduli of the ABNR and ZBNR increase to 1.125 TPa and 1.016 Tpa, respectively. The ultimate elastic strain for the ABNR increases to 18.23% but that for the ZBNR gets slightly reduced to 21.12%. The fracture modes still remain unchanged. The structural deformation after being subjected to a high temperature of 1500 K shows that there is little difference between the ABNRs and ZBNRs, but the structural deformation for the grafted BNRs is obviously less than that for the non grafted BNRs. The results indicate that grafting amine groups can increase the Young's moduli, enhance the elastic strain range, reduce the in-plane elastic anisotropy and strengthen the crack resistance. In particular, the grafting of amine groups can significantly strengthen their capacity to resist deformation at high temperature, reduce the thermal expansion anisotropy and improve the structural stability.