▎ 摘　　要

Atomically perfect graphene is one of the strongest materials ever measured. However, there remains a basic challenge to experimentally determine the inherent tensile strength of graphene nanoribbons, providing a benchmark for design of a variety of graphene-based structures. Using the atomic-scale characterization and in situ high-field tests in a field-ion microscope, it is shown that the inherent strength is 99.34 GPa and represents the intrinsic tensile strength of statistically defect-free graphene nanoribbons. The experimental results were compared with the theoretical data and found to be reliable. Mechanical failure of graphene ribbonss under tensile stress near the ideal strength determines a fundamental upper limit of internal stress in electromechanical graphene devices. (C) 2019 Elsevier B.V. All rights reserved.