Improved energy storage density in La-doped PbZr0.95Ti0.05O3 films with stress regulation

The Pb1-1.5xLaxZr0.95Ti0.05O3 films with different La3+ contents were successfully prepared on the LaNiO3/SiO2/ Si substrates by sol -gel method. The effect of La3+ doping on the microstructure, electrical properties, and energy storage performance of the films are systematically investigated. It is found that the introducing of La3+ with a smaller tolerance factor could enhance the lattice distortion and compressive stresses, leading to smaller grain size, slimmer electric hysteresis loops, and lower phase transition field hysteresis. As a result, a relatively high energy storage density of 30.2 J/cm3 together with the energy storage efficiency of 62.2% has been achieved in Pb0.82La0.12Zr0.95Ti0.05 antiferroelectric thin films with the optimum doping content. This improvement is largely attributed to the enhanced breakdown field strength from 1442 kV/cm to 1564 kV/cm as a result of grain size reduction. Our results demonstrate the crucial role of decreased tolerance factor in stabilizing the antiferroelectric phase and enhancing the phase transition electric field, and provide an effective route to enhance the energy storage performance of antiferroelectric thin films.