Broadband reflective bilayer polymer-stabilised cholesteric liquid crystal films capable of shielding visible and near-infrared laser light

In this paper, we propose a method to fabricate bilayer reflective broadband up to 1336 nm for PSCLC films. Unlike previous multilayer films, instead of using the polymeric network as the main diffusion channel for molecules between the upper and lower layers, the coverage of reflective bands in the partially visible and near-infrared regions is realised by the superposition of the upper and lower layers in conjunction with a small amount of diffusion of chiral molecules. We add the polymerisable chiral compounds and non-polymerisable chiral compounds with the same rotation direction into the liquid crystal mixing system of the upper and lower films respectively. Due to the presence of photoinitiators, when UV light irradiates the polymerisation, the polymerisable monomers including the polymerisable chiral compounds are rapidly polymerised in the near-light side, and the non-polymerisable monomers do diffusion movement to the near-light side, and the bilayer thin film forms the large-small-large pitch, thus realising broadband reflection. The bilayer PSCLC films reported in this study are expected to be promising candidates for a number of applications such as shielding infrared devices, energy-efficient windows for automobiles, and modern building facades.