摘要
Donor-acceptor co-doped rutile TiO_(2) ceramics with colossal permittivity(CP)have been extensively investigated in recent years due to their potential applications in modern microelectronics.In addition to CP and low dielectric loss,voltage stability is an essential property for CP materials utilized in high-power and high-energy density storage devices.Unfortunately,the voltage stability of CP materials based on codoped TiO_(2) does not catch enough attention.Here,we propose a strategy to enhance the voltage stability of co-doped TiO_(2),where different ionic defect clusters are formed by two acceptor ions with different radii to localize free carriers and result in high performance CP materials.The(Ta+Al+La)co-doped TiO_(2) ceramic with suitable La/Al ratio exhibits colossal permittivity with excellent temperature stability as well as outstanding dc bias stability.The density functional theory analysis suggests that La^(3+)Al^(3+)V_(0)Ti^(3+)defect clusters and Ta^(5+)-Al^(3+)pairs are responsible for the excellent dielectric properties in(Ta+Al+La)co-doped TiO_(2).The results and mechanisms presented in this work open up a feasible route to design high performance CP materials via defect engineering.
基金
financially supported by the Fundamental Research Foundation for University of Heilongjiang Province(No.2018-KYYWF-1628)
the National Natural Science Foundation of China(Nos.51471057 and 51677033)。
