The pseudocubic structure of a (Na 0.5 K 0.5 )NbO 3 (NKN) film grown on a Pt/Ti/SiO 2 /Si substrate changed to an orthorhombic structure when the film was transferred onto a polyimide substrate. Piezoelectric constant for the transferred NKN film increased considerably from 74 AE 11 to 120 AE 18 pm/V because the crystal structure of the film had changed from pseudocubic to orthorhombic. A gold interdigitated electrode was deposited onto the transferred NKN film to synthesize a NKN piezoelectric energy harvester. The NKN piezoelectric energy harvester was poled before bending under a 100 kV/cm DC electric field across the electrodes. When a strain of 0.85% and a strain rate of 4.05%/s were applied to the NKN piezoelectric energy harvester, it produced a maximum output voltage of 1.9 V and a current of 38 nA, corresponding to a power density of 2.89 lW/cm 3 .

Anatase TiO 2 nanoparticles, obtained by hydrolyzing titanium isopropoxide in distilled water, were used to synthesize BaTiO 3 (BT) nanopowder by the hydrothermal method. When titanium isopropoxide was used, BT nanopowder with a low tetragonality of 1.0070 was formed because of the presence of OHions in the oxygen sites and Ba vacancies. However, by changing the titanium source from titanium isopropoxide to TiO 2 nanoparticles, a homogeneous BT nanopowder with similar particle size and a high tetragonality of 1.0081 was synthesized. The size of the BT nanopowder particles was decreased by reducing the synthesis time. In particular, the BT nanopowder that was synthesized at 220°C for 16 h with a Ba/Ti molar ratio of 4.0 exhibited a high tetragonality of 1.0083 and a smallparticlesizeof126.0 nm. E. Suvaci-contributing editorManuscript No. 33609.

An amorphous phase was formed in a 0.95(Na 0.5 K 0.5 )NbO 3 -0.05CaTiO 3 (NKN-CT) film grown at 300°C, and a low-temperature transient Ca 2 Nb 2 O 7 phase was formed in the film grown at 500°C. In films grown at high temperatures (≥600°C), secondary phases such as K 5.75 Nb 10.85 O 30 and K 4 Ti 10 Nb 2 O 27 were developed without the formation of a NKN-CT phase, probably because of Na 2 O evaporation. The same secondary phases were formed in the film grown at 300°C and subsequently annealed at 850°C under an air atmosphere. However, a homogeneous NKN-CT phase was formed in films grown at 300°C and subsequently annealed at 830°C-880°C under the K 2 O and Na 2 O atmospheres. Moreover, the film annealed at 830°C in particular exhibited good electric and piezoelectric properties, including a high dielectric constant of 747 with a low dissipation factor of 0.93% at 100 kHz, low leakage current density of 2.0 3 10 -7 A/cm 2 at 0.1 MV/cm, and high P r and d 33 values of 15.4 lC/cm 2 and 124 pm/V at 100 kV/cm, respectively.