Controlling the Morphology of Nanoflakes Obtained by Liquid-Phase Exfoliation: Implications for the Mass Production of 2D Materials

Abstract

The heterogeneous nature of mass-produced 2D material’s nanoflakes requires analysis of size and shape parameters: their distributions around the desired values are essential for production and characterization. In this work, we obtain analytical expressions and behaviors of statistical distributions of experimentally extracted size and shape parameters of nanoflakes obtained by liquid-phase exfoliation. The collected data are open and can be mathematically handled to be analyzed through different associations in different scales, such as the logarithm of the length/thickness (r) and length/width (r L) aspect ratios. We find that ln­(r), a shape parameter, follows nearly Gaussian distributions, being an efficient fingerprint to characterize the material type and processing. On the other hand, the logarithms of thickness and volume follow asymmetric distributions with specific asymptotic behaviors, called exponential-power-Gaussian functions, but centrifugation turns both nearly Gaussian-distributed. Finally, the logarithm of the length/width aspect ratio, ln­(r L), an in-plane shape parameter, was found to follow the single-parameter probability density distribution xe–λx 2 . The method detected that centrifugation enhances, by up to threefold, the percentage of flakes with large length/width ratios. This statistical methodology can be incorporated into the quality control of mass production of 2D nanoflakes, whose target applications can be found across the fast-growing nanomaterials’ industry.

Aerosol-Printed MoS2 Ink as a High Sensitivity Humidity Sensor

“…Such value of ratio can be considered intermediate between the near-unity values of quantum-dot-type nanoparticles 44 and the values typically larger than 10 of nanoflake-type nanoparticles. 45 − 47 Previous investigations on films of quantum-dot-type MoS 2 nanoparticles have also reported humidity-dependent conductivities. 44 Therefore, we can consider the possibility that small aspect ratio values can be relevant to humidity sensing characteristics.…”

Deep‐learning‐based denoising approach to enhance Raman spectroscopy in mass‐produced graphene

“…Homogeneity is one of the most essential aspects in the quality control of mass‐produced graphene and requires statistical measurements for proper evaluation. Consequently, a critical aspect of quality control is the precise and efficient interpretation of large amounts of data generated by the characterization tools applied to mass‐produced graphene nanoflakes [1‐3] …”

“…Consequently, a critical aspect of quality control is the precise and efficient interpretation of large amounts of data generated by the characterization tools applied to mass-produced graphene nanoflakes. [1][2][3] Raman spectroscopy is the most spread technique applied to the study and characterization of graphenerelated structures. [4][5][6][7][8][9] Being non-destructive, it provides qualitative and quantitative information on structural parameters of graphene, mainly the number of layers and defect density.…”

High-Yield Production of Selected 2D Materials by Understanding Their Sonication-Assisted Liquid-Phase Exfoliation

“…A very promising method is the liquid-phase exfoliation (LPE) because it allows the possibility of upscaling and increasing the yields [22,[48][49][50][51]. Many articles on understanding the mechanism of LPE and advancing the yields of 2D materials have already been published [52][53][54][55][56][57][58][59],…”