Promoting polar rotation via antimony doping to enhance the pyroelectric performance of lead-free potassium sodium niobate ceramics

Abstract

Recently, lead-free pyroelectric ceramics have attracted increased attention in the context of pyroelectric infrared detector (PIRD) applications. Herein, the pyroelectric performance and evolution of phase structures for 0.995(K_0.48Na_0.52)_0.95Li_0.05Nb_1−xSb_xO₃–0.005BiAl_0.6Fe_0.4O₃ (KNLN_1−xS_x–BAFO, x = 0–0.04) ceramics are explored and enhanced pyroelectric performance when x = 0.02 is obtained, with a value of 3.14 × 10⁻⁴ C m⁻² K⁻¹ (Daglish method) and a separated intrinsic value of 2.5 × 10⁻⁴ C m⁻² K⁻¹. Moreover, the relationship between microstructure evolution and electric performance is investigated with Raman and positive up negative down (PUND) measurements, demonstrating the increased polar rotation and polarization. The role of Sb doping is closely related to the phase tuning ability and promotion of polar rotation in the ceramics with increased lattice distortion. Furthermore, the reversible and irreversible contributions of pyroelectric currents are discussed via different measurements and the thermally stimulated current is determined successfully, which provides practical benefits for investigating the intrinsic pyroelectric response of KNN ceramics in the future.