Pyroelectric properties of BST/PLT composite thick films with addition of xPbO–(1 − x)B 2O 3 glass

Abstract

The Ba x Sr 1− x TiO 3 (BST)/Pb 1− x La x TiO 3 (PLT) composite thick films (∼20 μm) with 12 mol% amount of xPbO–(1 − x)B 2O 3 glass additives ( x = 0.2, 0.35, 0.5, 0.65 and 0.8) have been prepared by screen-printing the paste onto the alumina substrates with silver bottom electrode. X-ray diffraction (XRD), scanning electron microscope (SEM) and an impedance analyzer and an electrometer were used to analyze the phase structures, morphologies and dielectric and pyroelectric properties of the composite thick films, respectively. The wetting and infiltration of the liquid phase on the particles results in the densification of the composite thick films sintered at 750 °C. Nice porous structure formed in the composite thick films with xPbO–(1 − x)B 2O 3 glass as the PbO content ( x) is 0.5 ≥ x ≥ 0.35, while dense structure formed in these thick films as the PbO content ( x) is 0.8 ≥ x ≥ 0.65. The volatilization of the PbO in PLT and the interdiffusion between the PLT and the glass lead to the reduction of the c-axis of the PLT phase. The operating temperature range of our composite thick films is 0–200 °C. At room temperature (20 °C), the BST/PLT composite thick films with 0.35PbO–0.65B 2O 3 glass additives provided low heat capacity and good pyroelectric figure-of-merit because of their porous structure. The pyroelectric coefficient and figure-of-merit F D are 364 μC/(m 2 K) and 14.3 μPa −1/2, respectively. These good pyroelectric properties as well as being able to produce low-cost devices make this kind of thick films a promising candidate for high-performance pyroelectric applications.