Improvements in piezoelectric and energy harvesting properties with a slight change in depolarization temperature in modified BNKT ceramics by a simple technique

For many BNT-based ceramics, an attempt to increase the piezoelectric properties usually results in a decrease in depolarization temperature (T(d)). This trend limits the applications of the materials. Many previous experiments have used different methods to enhance the piezoelectric properties and improve the T(d) characteristic. In this study, we demonstrated a simple technique (thermal annealing) to enhance the piezoelectric properties with a very slight decrease in T(d) by ∼2 °C for a modified BNKT ceramic (BNKT doped with ZnO). Other phase transition characteristic temperatures of the studied ceramics were also slightly changed. The optimum dielectric (ε(r) = 651, tan δ = 0.0503, T(F–R) = 167.38 °C, T(m) = 305.41 °C, ε(max) = 5551, T(B) = 367.15 °C, T(d) = 155.98 °C, and γ = 1.43), ferroelectric (P(max) = 41.28 μC cm(−2), P(r) = 35.85 μC cm(−2), E(c) = 42.60 kV cm(−1) and R(sq) = 1.42), piezoelectric (d(33) = 198 pC N(−1), k(p) = 0.598, and g(33) = 34.35 × 10(−3) Vm N(−1)), and energy harvesting (FoM = 6.80 pm(2) N(−1)) were obtained for the 8 h annealed ceramic. Furthermore, higher energy harvesting properties (which were 32% higher than that of the unannealed ceramic) were obtained after employing this technique.