Interface engineering and biphasic regulation synergistically enhance the energy storage performance of PVDF-based composites

With the rapid development of renewable energy systems and flexible electronics, polymer-based dielectric films integrating high energy density, superior charge-discharge efficiency, and multifunctionality have emerged as a critical frontier in materials science. In this study, we developed an interface-engineered PVDF/APTES@CsPbBr 3 organic-inorganic composite via an innovative in situ growth strategy of APTES-passivated perovskite quantum dots (QDs) within a PVDF matrix. The precisely controlled in situ synthesis enabled uniform QDs dispersion while establishing robust interfacial interactions. This synergistic design achieves dual enhancements by triggering pronounced polar-phase crystallization (>90 % β/γ-phase content) in PVDF to amplify dipole polarization and suppressing leakage pathways through QDs-induced nano-confinement effects. Remarkably, the composite exhibits a record-breaking energy storage density of 13.69 J/cm 3 at an electric field of 470 kV/mm with an ultrahigh efficiency of 85.03 %, surpassing most reported PVDF-based composites under comparable electric fields. Furthermore, the composite uniquely demonstrates temperature-stable ultraviolet fluorescence, a feature that not only confirms structural robustness but also enables real-time self-diagnosis of thermal degradation in optoelectronic devices. By integrating in situ -engineered interfaces, superior dielectric properties, and intrinsic optical sensing capabilities, this work establishes a transformative paradigm for intelligent energy materials in flexible electronics and self-monitoring power systems.