Nanoscale 0.94NBT–0.06BT near the Morphotropic Phase Boundary: Hydrothermal Design and Enhanced Ferroelectric Energy Conversion

Abstract Lead-free ferroelectric nanomaterials have attracted considerable interest for sustainable electronic and energy harvesting technologies. In this work, 0.94NBT–0.06BT nanoparticles were synthesized via a hydrothermal method and incorporated into a flexible Polyvinylidene fluoride (PVDF) matrix to fabricate a high-performance ferroelectric composite. X-ray diffraction confirmed the formation of a pure perovskite phase, while Rietveld refinement revealed the coexistence of rhombohedral (R3c) and tetragonal (P4mm) structures near the Morphotropic Phase Boundary region. Raman spectroscopy further verified the distorted lattice through characteristic TiO₆ vibrational modes. FESEM analysis showed uniformly distributed nanoparticles with an average size of ~ 167 nm and homogeneous dispersion within the PVDF matrix. The material exhibited strong ferroelectric behavior with a maximum polarization of 40 µC/cm 2 , remanent polarization of 33 µC/cm 2 , and coercive field of 26 kV/cm. The composite demonstrated promising energy harvesting capability, generating an open-circuit voltage of 4.47 V and a maximum power output of 2.57 µW at 35 Hz, highlighting its potential for flexible self-powered electronic devices.