Tuning of electrical properties of xBi(Zn0.5Ti0.5)O3-(1-x) (Ba0.5Sr0.5)TiO3 ceramics by composition design and bandgap engineering

Herein, the xBi(Zn0.5Ti0.5)O3-(1-x) (Ba0.5Sr0.5)TiO3 (x = 0.05, 0.10, 0.15, 0.20) novel negative temperature coefficient (NTC) ceramic materials were fabricated by solid-state method. X-ray diffraction revealed that xBi(Zn0·5Ti0.5)O3-(1-x) (Ba0.5Sr0.5)TiO3 successfully formed solid solution. The UV–vis diffuse spectra of the samples indicate that the band gap increases with the increasing Bi(Zn0·5Ti0.5)O3 content. The resistance temperature curve showed that with the increase of Bi(Zn0·5Ti0.5)O3 content, the resistivity ρ of the ceramics at 400 °C increased from 5.96 × 106 to 2.67 × 107 Ω cm, as well as an increase in the B400/800 from 12374.6 to 13469.1 K. The enhanced resistivity is attributed to the increased band gap and reduced carrier pairs caused by the Bi(Zn0.5Ti0.5)O3 modification. The impedance data indicates that the conduction process is activated by thermal. The ceramic samples exhibit the excellent NTC characteristics over a range of 400 °C–1000 °C. Hence, the xBi(Zn0.5Ti0.5)O3-(1-x) (Ba0.5Sr0.5)TiO3 ceramics have the potential to become high temperature NTC ceramics that can operate in a wide temperature range.