Enhancing nanostructure and energy harvesting efficiency in sustainable BCZT piezoelectric materials through calcination temperature optimization

Nanogenerators play a pivotal role in advancing sustainability by enabling wireless sensors to harvest energy from ambient sources. Optimizing their performance is crucial for enhancing energy conversion efficiency and ensuring reliable operation in real-world scenarios. Although calcination temperature has a critical parameter in the synthesis of piezoelectric materials that fundamentally determines their grain size, phase purity, crystalline structure, and, ultimately, their energy conversion efficiency, no studies have yet explored its potential to improve the performance of energy harvesters. This work investigates the influence of calcination temperature on the structural and functional properties of BCZT nanopowder, and its resulting energy conversion performance. Using the sol-gel method, BCZT powders were synthesized at temperatures ranging from 600°C to 1000°C. The results demonstrate that 900°C is the optimal calcination temperature, producing nanopowders with superior structural and functional characteristics. At this temperature, XRD and Rietveld refinement revealed an optimal morphotropic phase boundary with a crystal size of 18.16 nm, while SEM shows uniform particle distribution of around 68.9 nm, significantly smaller than the previously reported particle size achieved by the sol-gel method, which ranged from 0.8 μm to 60.5 μm. Furthermore, Raman spectroscopy confirmed high crystallinity and phase purity. Furthermore, Raman spectroscopy affirmed high crystallinity and phase purity. To better analyze the resulting properties in composite form, the different nanopowders were incorporated into the PDMS polymer. The BCZT-900/PDMS nanocomposite exhibits excellent energy harvesting properties, with a 100% increase in open-circuit voltage (7.8 V) and output power (4.52 μW) under cyclic loading. The device shows excellent durability over 5,000 cycles with a Young's modulus of 2.18 MPa and an elongation at break of 101.32%. An Ising-like model was also used to simulate the piezoelectric behavior, with the Hamiltonian solved by the Monte Carlo Metropolis method. The simulation results were in agreement with the experimental observations.