Outstanding enhanced breakdown field strength and energy storage properties in Na0.5Bi0.5TiO3-based thin film by the aging process
Aging behavior is usually perceived as a negative effect in application of ferroelectrics; however, we observe that the aging process has a unique role in improving the energy storage properties. Here, Na0.5Bi0.47La0.03TiO3 (NBLT) and Na0.5Bi0.5Ti0.97Mn0.03O3 (NBMT) thin films deposited on Pt/TiO2/SiO2/Si substrate are prepared by sol-gel method. There is a high growth rate of breakdown filed strengthen (BDS) and energy storage density (W) in aged NBMT thin film, its BDS and W are enhanced from 2175 kV cm-1 to 3492 kV cm-1, and from 16.1 J cm-3 to 37.7 Jcm-3, respectively. It is demonstrated that the aging process tends to exhibit various levels of sensitivity on doping sites due to the formation and orientation of the defect dipoles are different. Besides, (Na0.5Bi0.5Ti0.97Mn0.03O3/Na0.5Bi0.47La0.03TiO3)5 and 0.65 Pb (Mg1/3Nb2/3) O3-0.35PbTiO3/(Na0.5Bi0.5Ti0.97Mn0.03O3/Na0.5Bi0.47La0.03TiO3)3 [(M/L)5 and P/(M/L)3] are constructed to introduce interface to enhance BDS, where an outstanding energy density of 56.8 J cm-3 under 3579 kV cm-1 is achieved in aged P/(M/L)3 thin film. The aging process and introduction of interfaces are responsible for this improvement, and a possible mechanism for the aging process is proposed. It is concluded that the aging process combined with interface engineering is an effective strategy to improve energy storage properties.