Recently, Prof. Huai Yang and Prof. Shaojun Guo from the College of Engineering at Peking university have achieved important progress in the field of multi-responsive flexible liquid crystals smart films. They promoted a new procedure for making the flexible multi-responsive smart film containing tin doped indium oxide nanocrystals and phase-separated liquid crystals-polymer, which can reversibly control the passage of visible light by temperature and electric field, and also screen near infrared light. This work has been published in Materials Horizons (Impact Factor: 10.706), and the title of this paper is “A Temperature And Electric Field-Responsive Flexible Smart Film With Full Broadband Optical Modulation” (http://pubs.rsc.org/en/content/articlelanding/2017/mh/c7mh00224f#!divAbstract).
Figure 1. Surface treatment procedures for the ITO nanocrystals, the solar spectra of the as-prepared films under different optical conditions, the inter-structure of the as-prepared film and the photographs of the films under different temperatures and different applied voltages.
Smart windows, with abilities of achieving energy-saving and optimizing solar energy utilization, are playing a key role in reducing the overall energy spending and increasing comfort levels for people inside the building. However, the optical modulation of smart windows is usually constricted within a limited waveband, either visible (400-800 nm) or near infrared (NIR, 800-2500 nm) region, and also they must use additional energy to maintain the colored or transparent state. In this paper, Huai Yang and Shaojun Guo report a flexible multi-responsive smart film with a widest waveband modulation covering both visible and NIR region (400-2500 nm) reported to date, by creating the compatible interface between tin doped indium oxide (ITO) nanocrystals and polar syrup containing liquid crystals with a smectic A (SmA)/chiral nematic (N*) phase transition and photo-polymerizable monomers. The transmittance of as-made smart film can be thermally changed reversibly from highly transparent (78%) to strong light-scattering (1.5%) state in the visible region, and the light-scattering state of the film also can be regulated electrically. Moreover, more than 85% of the invisible NIR light can be efficiently shielded, resulted from a well-preserved localized surface Plasmon resonance from ITO NCs. The present work represents a key step forward towards preparing optical materials with multi-functional features for applications in energy-saving smart windows.
The first author of this work is Xiao Liang from the Department of Materials Science and Engineering of College of Engineering at Peking university, and this work was sponsored by the National Natural Science Foundation of China.