Temperature-dependent antiferroelectric properties in La³⁺ doped PbHfO₃ thin films with enhanced energy storage density and stability

Antiferroelectric thin films have attracted blooming interest due to their potential application in energy storage areas. Pb_(1−3x/2)La_xHfO₃ (PLHO-x, x = 0-0.05) thin films were fabricated on Pt(111)/TiO₂/SiO₂/Si substrates via the chemical solution deposition method. The x-ray diffraction and high-resolution transmission electron microscopy results show that the doping of La³⁺, which has a smaller ion radius, leads to a slight decrease in the lattice constant and unit cell volume, which can induce the lattice distortion. In addition, the dielectric and polarization properties indicate that with an increase in the temperature or La³⁺ content, the antiferroelectric (AFE) I phase can transform into an AFE II phase, exhibiting a slimmer P-E loop with enhanced switching field and more pronounced polarization dispersion. Notably, PLHO-0.04 showcases excellent energy storage performance (55 J/cm³, at 2.8 MV/cm). This material also exhibits good thermal, frequency, and fatigue stability. These results suggest that the energy storage performance of PbHfO₃-based films can be enhanced through the phase structure design, presenting a valuable approach to fulfill the growing demand for advanced energy storage devices.