Optimized piezoelectric and structural properties of (Bi,Na)TiO₃-(Bi,K)TiO₃ ceramics for energy harvester applications

다국어 초록 (Multilingual Abstract)

We investigated (1-x)(Bi,Na)TiO<SUB>3</SUB>-x(Bi,K)TiO<SUB>3</SUB> (x=0, 0.14, 0.16, 0.18, 0.20, and 0.22) compositions of lead-free piezoelectric ceramics for potential energy harvester applications. Composition and sintering temperature of (1-x)(Bi,Na)TiO<SUB>3</SUB>-x(Bi,K)TiO<SUB>3</SUB> were varied to extract the optimized processing temperature with each composition. We compared and analyzed sintering temperature-dependent surface morphologies and electrical properties. Maximum piezoelectric charge constant of 180pC/N were obtained from the 0.8(Bi,Na)TiO<SUB>3</SUB>-0.2(Bi,K)TiO<SUB>3</SUB>composition at the sintering temperature of 1180<SUP>o</SUP>C. Temperature dependent dielectric permittivity was measured to know the phase transition. We corresponded two different anomaly peaks, observed at 84 and 290<SUP>o</SUP>C, as the rhombohedral-tetragonal and tetragonal-cubic phase transitions, respectively. Due to these phase transitions, different shapes of polarization-electric field loops (P-E loops) were measured and compared. Finally, output power of 42.39nW/cm<SUP>2</SUP> were obtained for the (1-x)(Bi,Na)TiO<SUB>3</SUB>-x(Bi,K)TiO<SUB>3</SUB> lead free piezoelectric ceramics.