Rupture index: A quantitative measure of sub-micrometer cracks in graphene

By weight, graphene is stronger than steel; but the monolayer does crack with improper handling. Here, we introduce 'rupture index' as a parameter that quantifies the size and the density of cracks and related defects in graphene. The approach makes use of the high contrast achievable in fluorescence quenching microscopy to distinguish between graphene and the background substrate visible through graphene cracks. Rupture index is the only existing metric for quantifying the amount of cracks in graphene (and other 2D materials) to date; particularly, it serves to quantitatively assess and compare the efficiency of different handling processes, and to quantify the effect of the edges on the global properties (e.g. chemical reactivity, electrical or mechanical performance) of macroscale graphene sheets.

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