Unzipping chemical bond of non-layered bulk structures to form ultrathin nanocrystals

TL;DR

This paper introduces a novel technique to unzip ultra-thin nanocrystals from non-layered bulk structures, enabling the creation of 2D non-layered materials with distinct optical properties, expanding the 2D materials family.

Contribution

It demonstrates a new method to produce ultrathin nanocrystals from non-layered bulk structures, overcoming the challenge of strong chemical bonds.

Findings

Successfully unzipped ultrathin nanocrystals from non-layered structures.

Observed significant changes in optical properties compared to bulk materials.

Provided a versatile toolkit for synthesizing 2D non-layered nanomaterials.

Abstract

The rich electronic and band structures of monolayered crystals distinguished from their layered bulk counterparts offer versatile physical/chemical properties and applications.1-5 Their fabrications, particularly the top-down "exfoliations", are successful promised by the weak Van der Waals force between monolayers.6-9 Differentially, un-zipping ultra-thin crystals (e.g. with only one layer of crystal plane) from non-layered structures is highly challenging due to the strong chemical bond between planes and atoms. Alterative finely controlled growth of these ultra-thin materials is not really successful. This work demonstrates how a technique can be used to unzip and disintegrate ultra-thin crystal plane (e.g. monolayered nanocrystals and nanosheets) from bulk non-layered structures (ZnO, alpha/belta-MnO2, TiO2, alpha-TiB2), and present how the basic optical properties changed to distinguish from their bulk phases. The work here gives a strong tool kit to various novel 2D non-layered nanomaterials, providing significant contributions to the family of two-dimensional materials, potentially paving the way for various practical applications.