Ferroelectricity and Piezoelectric Energy Harvesting of Hybrid ABX-Type Halogenocuprates Stabilized by Phosphonium Cations.

Perovskite-structured compounds containing organic cations and inorganic anions have gained prominence as materials for next-generation electronic and energy devices. Hybrid materials possessing ferro- and piezoelectric properties are in recent focus for mechanical energy harvesting (nanogenerator) applications. Here, we report the ferroelectric behavior of ABX-type halogenocuprate materials supported by heteroleptic phosphonium cations. These lead-free discrete Cu(II) halides [PhMeP][CuCl] () and [PhMeP][CuBr] () exhibit a remnant polarization ( ) of 17.16 and 26.02 μC cm, respectively, at room temperature. Furthermore, flexible polymer films were prepared with various weight percentage (wt %) compositions of in thermoplastic polyurethane (TPU) and studied for mechanical energy harvesting applications. A highest peak-to-peak voltage output of 25 V and power density of 14.1 μW cm were obtained for the optimal 15 wt % -TPU composite film. The obtained output voltages were utilized for charging a 100 μF electrolytic capacitor that reaches its maximum charging point within 30 s with sizable stored energies and accumulated charges.