Two-dimensional Functional Minerals for Sustainable Optics

TL;DR

This paper introduces sustainable two-dimensional mineral-based inorganic liquid crystals, specifically vermiculite, which enable low-energy, environmentally friendly optical devices with tunable properties, offering a promising alternative to organic liquid crystals.

Contribution

The study demonstrates the synthesis and characterization of vermiculite-based 2D mineral liquid crystals with enhanced magneto-birefringence for sustainable optical applications.

Findings

Vermiculite exhibits high size-to-thickness ratio and optical bandgap.

It shows significantly larger magneto-birefringence than organic counterparts.

Enables fabrication of low-energy chromic optical devices.

Abstract

Optical device is a key component in our lives and organic liquid crystals are nowadays widely used to reduce human imprint. However, this technology still suffers from relatively high costs, toxicity and other environmental impacts, and cannot fully meet the demand of future sustainable society. Here we describe an alternative approach to colour-tuneable optical devices, which is based on sustainable inorganic liquid crystals derived from two-dimensional mineral materials abundant in nature. The prototypical two-dimensional mineral of vermiculite is massively produced by a green method, possessing size-to-thickness ratios of >103, in-plane magnetisation of >10 emu g-1, and an optical bandgap of >3 eV. These characteristics endow two-dimensional vermiculite with sensitive magneto-birefringence response, which is several orders of magnitude larger than organic counterparts, as well as capability of broad-spectrum modulation. Our finding consequently permits the fabrication of various chromic devices with low or even zero-energy consumption, which can be used for sustainable optics.