Harnessing Multi-Effect Coupling for Deep-Level Trap Engineering in Graphene/Liquid Crystal Polymer Composites Toward High-Fidelity Electrostatic Loudspeakers.

Electrostatic loudspeakers (ESLs) demand lightweight, robust diaphragms with stable high-density charge storage, yet conventional electrets suffer from rapid charge dissipation, shallow trap levels, and severe environmental sensitivity. This work reports a microstructural regulation strategy based on the strong interaction between liquid crystal polymer (LCP) and multilayer graphene (MLG), combined with fluorinated liquid crystals (F-LC). The strong π-π stacking interaction between the rigid mesogenic units of LCP and MLG modulates the band structure of MLG and induces Maxwell-Wagner-Sillars (MWS) interfacial polarization. It constructs deep-level charge traps and increases the density of charge traps. The strong electrostatic attraction of F-LC enhances charge-trapping capability and improves the hydrophobicity of the composite, delivering superior environmental stability. Thermally stimulated discharge current (TSDC) measurements confirm a trap energy level of 1.8 eV, with an average absolute surface potential of 8.7 kV. The resulting electrostatic loudspeaker achieves a maximum sound pressure level (SPL) of 91.4 dB at 775 Hz and extremely low total harmonic distortion (THD < 0.53%) over a wide frequency range (3-20 kHz). This work provides a promising pathway for high-fidelity, bias-free flexible acoustic transducers, overcoming the long-standing bottleneck for ESLs in consumer and automotive applications.