Lead-free Bi-based complex perovskite nanowires: Sol–gel-hydrothermal processing and the densification behavior

One dimensional ferroelectric nanostructure is noteworthy for their size-dependent dielectric, piezoelectric, and electro-optic properties with corresponding applications in smart devices such as transducers, actuators, and high-k dielectrics at the nanoscale. Due to their extremely small size and anisotropy, the control of nucleation and growth of one dimensional nanostructure materials is still a big challenge. Sol–gel-hydrothermal chemistry combines both the merits of sol–gel and hydrothermal technique, which offers a very useful tool for low-temperature synthesis of the ferroelectric nanowires. In this paper, we will review recent works devoted to the synthesis of Bi-based complex perovskite nanowires, i.e. Na_0.5Bi_0.5TiO₃, K_0.5Bi_0.5TiO₃, (K_0.5Bi_0.5)_0.4Ba_0.6TiO₃ and (Na_0.8 K_0.2)_0.5Bi_0.5TiO₃ systems. We will focus on the formation mechanism and morphology evolution of nanowires prepared in sol–gel-hydrothermal process. Moreover, due to the good sinterability of the nanowires, the high-densified single-phase ceramic can be fabricated even by a conventional sintering process.