Energy Storage Properties And Negative Electrocaloric Effect Of PEZST Antiferroelectric Films

With the rapid development of microelectronic system,local cooling of microworking devices is very important.Meanwhile,the rapid development of pulse power technology puts forward higher requirements for energy storage dielectric materials.Antiferroelectric thin films have a promising application in energy storage and negative electrocaloric effect,owing to the unique field-induced phase transition characteristics.Based on the zirconium-rich PbZr_0.97Ti_0.03O₃ anti-ferroelectric thin films,the phase transition behavior of the thin films is regulated by doping and substitution method,so as to optimize the energy storage properties and negative electrocaloric effect of the thin films.In this paper,the sol-gel method combined with rapid annealing process was used to prepare the thin films of Eu doped?Pb,Eu?(Zr_0.97Ti_0.03)O₃?PEZT?films,Sn substituted Pb?Zr,Sn,Ti?O₃?PZST?films and Eu doped and Sn substituted composite?Pb,Eu??Zr,Sn,Ti?O₃?PEZST?films on Pt?111?/Ti/SiO₂/Si substrate.In order to prepare a single perovskite structure thin film,the preparation process of thin films was optimized in this paper.By analyzing the dielectric temperature spectrum and dielectric spectrum of modified thin film samples,the influences of single doping substitution mode and composite modification mode of Eu and Sn on Curie temperature,dielectric constant and dielectric loss of thin film were studied.In order to study the phase change electric field of the thin film,the hysteresis loop of different electric field and temperature were tested,and the influence of electric field,temperature and modifier were analyzed.And these factors on the antiferroelectric-ferroelectric phase change electric field and ferroelectric-antiferroelectric phase of the thin film sample were investigated.The recoverable energy storage density,energy storage loss,energy storage efficiency and negative electrothermal temperature variation of modified thin film samples were studied by using electric hysteresis loops at different electric fields and temperatures.Furthermore,the effects of electric field,temperature and modifier on the energy storage performance of PZT97/3 thin film samples were further analyzed.Through the maximum negative electrothermal entropy change value,maximum negative electrothermal temperature change value and temperature change corresponding to the maximum negative electrothermal temperature change value,the influence of single doping substitution mode of Eu and Sn and composite modification mode on the negative electrothermal effect of thin films was comprehensively analyzed and evaluated.The results of this experiments indicate that the energy storage performance and negative electrocaloric effect of zirconium-rich PZT anti-ferroelectric thin film can be optimized by adjusting the doping substitution amount of Eu and Sn.In terms of energy storage performance,the PEZST15 film doped by 0.5 mol%Eu and replaced by 15 mol%Sn reached the optimal level,and the recoverable energy storage density reached 26.66 J/cm³ at 900 kV/cm.For negative electrocaloric effect,the maximum negative electrothermal temperature change value of PEZST20composite films could reach-7.31K when the doping amount of Eu was 0.5 mol%and substitution amount of Sn was 20 mol%.