Breaking dielectric dilemma via polymer functionalized perovskite piezocomposite with large current density output

Organometal halide perovskite (OHP) composites are flexible and easy to synthesize, making them ideal for ambient mechanical energy harvesting. Yet, the output current density from the piezoelectric nanogenerators (PENGs) remains orders of magnitude lower than their ceramic counterparts. In prior composites, high permittivity nanoparticles enhance the dielectric constant (ϵ_r) but reduce the dielectric strength (E_b). This guides our design: increase the dielectric constant by the high ϵ_r nanoparticle while enhancing the E_b by optimizing the perovskite structure. Therefore, we chemically functionalize the nanoparticles to suppress their electrically triggered ion migration for an improved piezoelectric response. The polystyrene functionalizes with FAPbBr₂I enlarges the grains, homogenizes the halide ions, and maintains their structural integrity inside a polymer. Consequently, the PENG produces a current density of 2.6 µAcm^-2N^-1. The intercalated electrodes boost the current density to 25 µAcm^-2N^-1, an order of magnitude enhancement for OHP composites, and higher than ceramic composites.