Ferroelectricity and Piezoelectric Energy Harvesting of an A3M2X9-type 0D Bromobismuthate Hybrid with Bulky Organic Quaternary Amine

Organic-inorganic hybrid ferroelectric compounds of the halobismuthates family have emerged as a focal point of research owing to their reduced toxicity and distinctive optical characteristics. This study presents a novel ammonium hybrid perovskite, [BPMBDMA]∙[Bi₂Br₉], which exhibits both ferro- and piezoelectric properties and crystallizes in the polar noncentrosymmetric Pca2₁ space group. The nonlinear optical (NLO) activity of [BPMBDMA]∙[Bi₂Br₉] was corroborated through second harmonic generation measurements evidencing its noncentrosymmetric structure, which was further substantiated by piezoresponse force microscopy analyses. Ferroelectric P-E hysteresis loop investigations conducted on a thin film sample of [BPMBDMA]∙[Bi₂Br₉] revealed a saturation polarization (P_s) as much as 11.30 µC cm⁻² at ambient temperature. To explore the piezoelectric energy harvesting capabilities of [BPMBDMA]∙[Bi₂Br₉], composite materials were fabricated using polylactic acid (PLA) as a matrix. Notably, a device comprising 10 wt% [BPMBDMA]∙[Bi₂Br₉] in PLA demonstrated a remarkable output voltage of 24.6 V and a peak power density of 13.65 µW cm⁻². The practical applicability of this device’s output performance was further evaluated through a capacitor charging experiment, wherein a 10 µF capacitor was charged within 160 seconds.