Simultaneous achievement of high visible transmission and near-infrared heat shielding in flexible liquid crystal-based smart windows via electrode design. (August 2019)

• Record Type: Journal Article
• Authors: Huang, Jinhua; Li, Jia; Xu, Junjun; Wang, Zhaozhao; Sheng, Wei; Li, Hongjiang; Yang, Ye; Song, Weijie
• Is Part Of: Solar energy. Volume 188(2019)
• Page Start: 857
• Page End: 864
• Publication Date: 2019-08
• Subjects: Smart window -- Polymer dispersed liquid crystals -- Ultrathin Ag electrode -- Heat shielding; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2019.06.063
• Languages: English
• ISSNs: 0038-092X

Abstract

Highlights: Ultra-thin Ag films were achieved by introducing Cu dopant. TiO2 /Ag(Cu)/TiO2 (TCAT) electrode was designed and optimized for PDLC device. TCAT based PDLC device reached high transmittance of 84.9% at ON state. TCAT based PDLC device exhibited excellent heat shielding performance. TCAT based PDLC device exhibited 4.6 °C lower temperature than ITO counterpart. Abstract: Light and heat management are the two vital requirements for smart window towards ideal solar control. However, as a representative polymer dispersed liquid crystal (PDLC) device, little attention has been paid to heat management. Herein, a TiO2 /Ag(Cu)/TiO2 (TCAT) electrode was designed and optimized to achieve the tunability of transmission in visible range and near-infrared heat shielding simultaneously. The continuous growth of ultrathin Ag films with low percolation threshold was achieved on TiO2 underlayer by doping a certain amount of Cu. Then the trade-off of PDLC devices' optoelectrical properties was realized. The average ON state specular transmittance of TCAT-based PDLC devices reached 81.9%, 84.9%, 81.9% and 79.9% for Ag(Cu) thicknesses of 7 nm, 9 nm, 11 nm and 13 nm, respectively. In addition, TCAT electrodes exhibited satisfactory ratio of light to solar gain by taking visible transmittance and solar heat gain coefficient into comprehensive consideration. Compared with ITO-based PDLC counterpart, a notable temperature-decreases of 4.6 °C was observed at ON state of TCAT-based device, indicating an excellent heat shielding performance. The proposed TCAT electrode design is promising in smart window application especially for building energy conservation in hot areas or the summer season.