A Spectrum-Tailored Polymer Dispersed Liquid Crystal Film for Energy-Saving Smart Windows

The polymer dispersed liquid crystal (PDLC) holds potential application in smart windows, owing to its feasibility in regulating the transmittance of specific wavelength bands to improve energy utilization. Herein, a composite PDLC smart window is designed, which showcases high emissivity of 93.79% in the mid-infrared region and features the regulation of ultraviolet (UV), visible, and near-infrared (NIR) light. Titanate nanomaterials with diverse morphologies are synthesized and doped to endow the PDLC film with perfect UV shielding property and excellent electro-optical (E-O) performance. Subsequently, the E-O performance is further improved by modifying the structure of acrylate monomers, with the maximum transmittance exceeding 80%. Furthermore, the LaB₆ layer is incorporated to effectively shield NIR light. Due to the synergistic effect of sunlight modulation and passive radiative cooling, the composite PDLC smart window can effectively lower the indoor temperature compared with traditional PDLC films. Eventually, the fabricated LaB₆/PVA/PDLC smart window displays high contrast (210.65), a low threshold voltage (6.68 V), and remarkable passive radiative cooling performance (cooling power of 131.24 m² K^-1). Overall, the composite presents switchable transmittance in visible region, excellent UV-blocking (>99%), and high NIR shielding capacities, thereby broadening its potential application in the field of smart windows.