Enhanced Pyroelectric Performance of Lead-Free Zn-Doped Na1/2Bi1/2TiO3-BaTiO3 Ceramics

Lead-free Na₁/₂Bi₁/₂TiO₃-BaTiO₃ (NBT-BT) has gained revived interest due to its exceptionally good high power properties in comparison to commercial lead-based piezoelectrics. Recently, Zn-modified NBT-BT-based materials as solid solution and composites have been reported to exhibit enhanced depolarization temperatures and a high mechanical quality factor. In this work, the pyroelectric properties of Zn-doped NBT-6mole%BT and NBT-9mole%BT ceramics are investigated. The doped compositions of NBT-6BT and NBT-9BT feature a relatively stable pyroelectric property in a wide temperature range of ~37 K (300–330 K) and 80 K (300–380 K), respectively. A threefold increase in detector figure of merit is noted for 0.01 mole Zn-doped NBT-6mole% BT at room temperature in comparison to undoped NBT-6mole%BT and this increase is higher than those of major lead-free materials. A broad range of the temperature-independent behavior for the figures of merit was noted (303–380 K) for Zn-doped NBT-6mole% BT, which is 30 K higher than the undoped material. The large pyroelectric figures of merit and good temperature stability renders Zn-doped NBT-BT an ideal candidate for pyroelectric detector and energy harvesting applications

Solar energy harvesting using lead-free pyroelectric bulk ceramics: A simulation study

Solar radiation and wind provide the temporal temperature fluctuation for heating and cooling. 0.005La–Na0.5Ba0.5TiO3-0.06BaTiO3-0.002Ta is found as the best suitable material for energy harvesting. The voltage and power output are further improved by tuning operating frequency, load capacitance and resistance. Maximum power of 6.7 μW is obtained at a frequency of 0.04 Hz, load capacitance of 1 μF and resistance of 25 MΩ. A nonlinear electrical circuit based on parallel synchronized switched harvesting on the inductor (P–SSHI) and hybrid synchronized switched harvesting on the inductor (H–SSHI) are used to enhance the power. The power is increased by 54% and 34.6% under P–SSHI and H–SSHI, respectively. However, H–SSHI was preferred for power-boosting because of the self-triggering process and low energy losses. This work shows the potential of lead-free pyroelectric materials for solar energy harvesting with losses in the circuit