Single layer graphene has nanoscale pores, atomic level thickness, and significant mechanical properties, providing a wide range of application opportunities for ion and molecular separation, energy storage, and electronics. To a large extent, because the performance of these applications depends on the size of the nanopores, it is desirable to precisely design and manufacture suitable nanopore sizes with narrow size distributions. However, the traditional top-down preparation process typically produces a log normal distribution with a long tail, especially at the sub nanometer scale. In addition, fundamentally, the size distribution and density of nanopores are interrelated, requiring a trade-off between the two, which greatly limits their applications.
Today, Jiangtao Wang, Jing Kong, and others from the Massachusetts Institute of Technology in the United States, as well as Chi Cheng (first author) from the University of Melbourne in Australia, reported in Nature a cascaded compression method to reduce the size distribution of nanopores with left skewed skewness and ultra small tail deviations, while increasing the nanopore density in each compression cycle.
The formation process of nanopores can be divided into many small steps. In each small step, a combination of shrinkage and expansion is used to compress the size distribution of all existing nanopores, and while expanding, a batch of new nanopores are generated, thereby increasing the nanopore density in each cycle. Research has shown that high-density nanopores with left skewed and short tailed size distributions have been obtained in single-layer graphene, demonstrating ultrafast and Emi scale selective transport of ions and molecules, breaking the traditional limitations of log normal size distributions.
This method independently controls several parameter indicators for generating nanopores, including density, average diameter, standard deviation, and skewness values of size distribution, which will lead to the next leap in nanotechnology.
Figure 1: Schematic diagram of compression cycles generated by nanopores in single-layer graphene.
Figure 2: Characterization of Nanopores and Validation of Cascade Compression Model.
Figure 3: Based on the size distribution and density of separated nanopores, solvent permeation and ultrafast nanofiltration.
Figure 4: Highly adjustable and selective solute permeation exceeds the logarithmic normal limit.
Editor: Sichuan Jinzhongde Science and Technology Research Institute
Source: High functional film
