High‐Performance Flexible Pyroelectric Energy Harvesting System Enabled by Light‐Driven Thermomechanical Coupling in Liquid Crystal Elastomer

Liquid crystal elastomers (LCEs) with reversible thermal actuation are promising platforms for multifunctional flexible electronics. Herein, we present a PVDF/LM-LCE (PVDF, polyvinylidene fluoride; LM, liquid metal) composite in which PVDF is polymerized in situ within the LCE matrix to achieve seamless mechanical coupling and efficient stress transfer. LM nanodroplets enhance mechanical robustness, charge transport, and photothermal conversion, enabling LCEs to serve as photothermally driven transducers that amplify the piezoelectric and pyroelectric outputs in these flexible systems. The optimized composite achieves a pyroelectric coefficient of -4.81 nC·cm^{- 2}·K^{- 1}, 1.8 times higher than conventional PVDF films. Furthermore, the composite device powers two LEDs and digital sensors using low-grade photothermal fluctuations. This LCE-based light-driven thermomechanical-to-electrical conversion strategy offers a generalizable pathway for high-performance, flexible pyroelectric and piezoelectric energy-harvesting materials.