Pyroelectric performance of zinc oxide-added 0.94Na_0.5Bi_0.5TiO₃–0.06BaTiO₃ composite

The pyroelectric material generates voltage/current in response to the thermal gradient, an effective technique for sensors and waste thermal energy harvesting. In this regard, 0.94Na_0.5Bi_0.5TiO₃–0.06BaTiO₃–xZnO (NBT–6BT:xZnO, x = 10, 20, 30, and 40) composites were analyzed for pyroelectric performance. The NBT–6BT:10ZnO composite consists of a maximum depolarization temperature and pyroelectric coefficient of 139 °C and 2.90 × 10⁻⁴ C/m² K, among other composites. The depolarization of NBT–6BT:xZnO showed different behaviors for low mole fraction of ZnO (x = 10, 20) and higher mole fraction of ZnO (x = 30, 40). The pyroelectric figures of merit for voltage sensitivity (F_v) and energy harvesting (F_e*) were further enhanced by layered porosity. Repeatable poling is achieved by layered porosity, which is always a barrier to porous material. A custom-built heating/cooling setup was used to measure the actual pyroelectric current/voltage response; the maximum 90 V and 120 V were obtained for NBT–6BT:10ZnO mixed with 2% (10.7% porous) and 12% (28% porous) polymethyl methacrylate (PMMA).