Electro-dimming liquid crystals for thermal management smart windows

Thermal management smart windows can dynamically regulate solar radiation transmission and indoor–outdoor heat exchange, offering an effective route to reduce energy consumption in buildings and vehicles. Electro-dimming liquid crystals achieve reversible modulation of light scattering, reflection, and absorption through electric-field-induced molecular reorientation, phase transitions, or ordered structural changes. Active controllability, rapid response, and device-integration compatibility make electro-dimming liquid crystals promising materials for thermal management smart windows. The review summarizes recent progress in electro-dimming liquid crystals, with emphasis on dimming mechanisms, structural regulation strategies, and thermal management applications. Based on material composition and structural characteristics, electro-dimming liquid crystal systems are classified into liquid crystal/polymer composites and polymer-free liquid crystal systems. For liquid crystal/polymer composites, substituent regulation, fluorinated monomer regulation, and copolymer system regulation are discussed in relation to electro-optical performance. Functional fillers, alignment interfaces, and layered structures are further analyzed for near-infrared (NIR) modulation, radiative cooling, and wide-temperature-range stability. For polymer-free liquid crystal systems, polar structures, two-dimensional (2D) ordered structures, helical superstructures, and composite components are reviewed in terms of low-field response, multistability, selective reflection, absorption/scattering regulation, and structural stability. Remaining challenges and future directions are finally outlined.