Ferroelectricity and piezoelectric energy harvesting of an A3M2X9-type 0D bromobismuthate hybrid with a bulky organic quaternary amine†

Abstract

Organic–inorganic hybrid ferroelectric compounds of the halobismuthate 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.