Study on cuo doping effect on 0.69PZT-0.31PZNN for multi-layer piezoelectric energy harvesting system

In this study, we have investigated CuO doping effect on PZT-PZNN thick film for lower temperature sintering of multi-layer structure energy harvesting system. We prepared 0.69PZT-0.31PZNN powder, slurry, and green sheet to manufacture thick film ceramics with different doping amount of CuO. Various amount of CuO (0, 1, 2 and 3 mol%) were inserted into piezoelectric material composition of (Zr_0.47Ti_0.53)O_3- 0.31Pb {(Ni_0.6Zn_0.4)_1/3Nb_2/3}O₃. Laminated thick films with thickness of 0.310 mm were sintered at 900°C. Microstructures were investigated by using SEM and XRD. Also, dielectric property of sintered samples was measured by using d₃₃ meter. As results, dielectric permittivity increases as CuO doping amount increases, which led to decrease in resistance and increase in capacitance value. CuO doping amount of 2 mol % was found to be the optimized point with the highest d₃₃ value. This was explained by SEM images. The SEM images showed the increasing grain size as the CuO doping amount increase, and as the doping amount was 2 mol % or higher, secondary phase was observed in XRD. After measuring and analyzing the CuO doped samples, 2 mol% CuO doped PZT-PZNN thick film was placed on a SUS301 substrate to perform as a unimorph cantilever type energy harvesting system. First, the resonance frequency was observed in 39 Hz with 10.4V. At the resonance frequency, the impedance matching was found at the 2 M Ω, which the output power was calculated as 8 μW. This output power was then calculated as 0.267 mW/cm³.