A Highly Electrostrictive A₂BX₄-Type Hybrid 2D Perovskite Ferroelectric and the Utility of Its Piezoelectric Nanogenerator in Wireless Mat-Sensor Technology

High Resolution Image Download MS PowerPoint Slide The quasi-spherical theory and ligand halogenation have emerged as effective strategies for promoting polar noncentrosymmetric structures with potential ferroelectric properties. Here, we report a novel two-dimensional (2D) hybrid organic–inorganic perovskite, [ p -ClBnNH 3 ] 2 CdBr 4, in the polar orthorhombic Ccc 2 space group. The structural noncentrosymmetry was confirmed via second harmonic generation (SHG) measurements. Polarization-electric field ( P–E ) hysteresis measurements revealed a saturation polarization ( P s ) of 1.28 μC cm –2 at room temperature. Furthermore, it exhibits a high electrostrictive coefficient ( Q 33 ) of 3.6 m 4 C –2, surpassing those observed in traditional ferroelectrics. For energy harvesting applications, composite films were fabricated by embedding [ p -ClBnNH 3 ] 2 CdBr 4 in thermoplastic polyurethane (TPU) matrix. The 10 wt % device yielded a piezoelectric nanogenerator (PENG) output voltage of 20.0 V and a power density of 67.6 μW cm –2 . A prototype “mat-sensor”, which is a scalable smart force sensor, was developed, demonstrating rapid response and wireless functionality for real-time applications, including security systems.