Preparation And Energy Storage Properties Of PbZrO₃-based Antiferroelectric Thin Films

PbZrO₃(PZO)based antiferroelectric materials have field induced phase transition process of antiferroelectric-ferroelectric,resulting in a significant increase in energy storage and release.Therefore,they have broad application prospects in the field of dielectric capacitor energy storage.This thesis aims to construct multiphase coexisting PZO based solid solution antiferroelectric films by element doping,so as to improve the energy storage performance of PZO based antiferroelectric thin films at different application electric fields.(1)For the application of micro capacitors in low electric field,Pb Sn O₃(PSO)was doped into PZO to form multi-phase coexisting antiferroelectric solid solution films,and controlling the concentration of PSO can change microstructures and electrical properties of(1-x)PZO-x PSO antiferroelectric films;(2)The doped Sr Ti O₃(STO)into PZO can lead to multi-phase coexistence in PZO-STO solid solution composite films,which can improve energy storage performance of the films at high electric field.Specific research contents and results are as follows:(1)PSO was doped into PZO to form PZO-PSO antiferroelectric solid solution films,and the effect of PSO concentration on the microstructures and electrical properties of the solid solution films were studied.The results showed that Sn⁴⁺with small ion radius entered into the PZO lattice to replace Zr⁴⁺,which increased the tolerance factors of the thin films,reduced the electric field of transition from AFE to FE phase,and achieved saturation polarization under low electric field,so as to improve the energy storage density of the thin films.In addition,the coexistence of tetragonal phase and orthorhombic phase in the PZO-PSO thin films can result in dispersion phase transition,thereby improving energy storage efficiency of the thin films.When the content of PSO was 0.48,the maximum energy storage density and efficiency were 6.11 J/cm³and 72%respectively,which were 68.26%and 10%higher than the pure PZO films at low electric field of 333 k V/cm.(2)The effect of STO concentrations on the microstructures and electrical properties of PZO-STO solid solution thin films were studied.The results showed that mesophase of Sr₄Zr₃O₁₀ with perovskite structure were formed in the PZO-STO thin films after STO doping,thus forming a multiphase structure.With the increase of STO concentration,the grain size of thin film decreased gradually,contributing to breakdown field strength of thin films.In addition,Mesophores break the long-range ordered FE dipoles in films,and the local random fields generated by the structural changes around the substituted ions lead to the appearance of polar nano-regions in the films,thus leading to RFE behavior and optimizes the energy storage efficiency of the films.When the STO content was 20%,the films had the maximum recoverable density and energy storage efficiency were 15.26 J/cm³and 61.64%,which increased by 117.14%and 54.44%compared with pure PZO film,respectively.(3)The effect of crystallization temperature on microstructures and electrical properties of 0.8PZO-0.2STO solid solution thin film was studied.The results showed lager grain size was observed in thin films at high crystallization temperature,which resulted in the increase of the maximum polarization and decreased of the breakdown electric field.When the crystallization temperature was 600?,the 0.8PZO-0.2STO thin films had the maximum breakdown field strength,which was 2342.76 k V/cm.When the crystallization temperature was 625?,the films had the maximum breakdown electric field,which was 1743.54k V/cm,and an obvious relaxation behavior.Meanwhile,it exhibited the best energy storage density and energy storage efficiency,which were 25.55 J/cm³ and 46.53%,respectively.