Liquid Crystals as Functional Ordered Media for Energy Devices: Bridging Ionics, Electronics, and Photonics

Liquid crystals (LCs) combine fluid-like processability with programmable orientational and positional order, enabling molecular organization to be translated into directional transport pathways, adaptive interfaces, and field-responsive optical states. This review examines thermotropic and lyotropic LCs as functional ordered media for energy storage, photovoltaic conversion, and adaptive optical/thermal management. A mechanistic framework is established around mesophase topology, local chemical environment, and processing-dependent structural persistence, with particular emphasis on distinguishing experimentally demonstrated mechanisms from interpretation based primarily on modeling or indirect correlations. In electrochemical storage, LC architectures regulate ion-pathway connectivity, solvation, water activity, electrodeposition, and interphase evolution. In perovskite and organic photovoltaics, LC additives, interlayers, and elastomeric networks influence defect chemistry, crystallization, molecular packing, energetic losses, and mechanical stability. Dye-sensitized solar cells provide a distinct case in which ordered electrolytes regulate redox-ion transport, whereas smart windows and related adaptive systems exploit LC reorientation, scattering, absorption, and phase transitions to control light and heat. Across these applications, performance is governed by recurring trade-offs among transport, structural fixation, interfacial selectivity, optical loss, and processing tolerance. By combining mechanistic evidence with standardized performance metrics and application-specific selection criteria, this review provides a practical framework for designing LC-enabled energy materials beyond device-specific empirical optimization.