A Chiral Edge-Sharing Bioctahedral Chlorobismuthate(III) Hybrid Ferroelectric and Its Application in Piezoelectric Energy Harvesting

Abstract

Halogenobismuthate(III)-based organic–inorganic hybrid ferroelectrics integrate molecular dipoles arising from organic cations with intrinsic polarization originating from the inorganic backbones, offering a promising avenue for the development of environmentally benign and structurally tunable materials for advanced electronics. Although their potential in piezoelectric energy harvesting has rarely been explored, this study presents a novel chiral ammonium chlorobismuthate(III), [(S)-NEA]4[Bi2Cl10] ((S)-NEA represents (S)-1-(naphthalen-2-yl)ethan-1-ammonium), crystallizing in the polar space group P21 and exhibiting ferroelectric properties. Its noncentrosymmetric structure was further confirmed by second harmonic generation (SHG) measurements. Ferroelectric characterization using P–E hysteresis loop measurements revealed a saturation polarization (Ps) of 3.8 μC cm–2. The microscopic ferroelectric domain structure was confirmed by the piezoresponse force microscopy (PFM) studies. For energy harvesting, [(S)-NEA]4[Bi2Cl10] was incorporated into a polycaprolactone (PCL) matrix to fabricate piezoelectric nanogenerator (PENG) devices. The composite with 15 wt % [(S)-NEA]4[Bi2Cl10] device exhibited the highest output voltage of 15 V, current density of 3.2 μA cm–2, and power density of 4.6 μW cm–2. The device demonstrated notable sensitivity and responsivity (0.44 V N–1 and 274.9 V MPa–1, respectively), a fast response time of 14.5 ms, and efficient energy storage, charging a 22 μF capacitor with 0.50 μJ within 400 s.