HU B F, WEI H R, YANG Z W,et al.Optical transmittance， dielectric properties and impedance spectroscopy of （1-x）(K_0.5Na_0.5）NbO₃-xSr_0.7La_0.2ZrO₃ ceramics[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(3):179-187.

doi:10.16186/j.cnki.1673-9787.2024020028

Received:2024/02/28

Revised:2024/05/06

Published:2026/04/28

Optical transmittance， dielectric properties and impedance spectroscopy of （1-x）（K_0.5Na_0.5）NbO₃-xSr_0.7La_0.2ZrO₃ ceramics

Hu Baofu, Wei Houren, Yang Zaiwen, Liu Bingguo, Xu Jian, Wang Jian, Du Baoli

School of Physics & Electronic Information Engineering， Henan Polytechnic University， Jiaozuo 454003， Henan， China

Abstract: Objectives To investigate the optical transmittance， conduction mechanism， and dielectric relaxation behavior of （K_0.5Na_0.5）NbO₃-xSr_0.7La_0.2ZrO₃ （KNN-SLZ） ceramics.  Methods Lead-free KNN-SLZ ceramics were prepared by a conventional solid-state method. The microstructure was tailored by introducing Sr_0.7La_0.2ZrO₃（SLZ）. The phase structure and morphology were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The optical transmittance and dielectric properties were measured using a UV-Vis-NIR spectrophotometer and an LCR meter， respectively. Temperature-dependent impedance and electric modulus spectra were analyzed using an impedance analyzer.  Results The KNN-SLZ ceramics exhibit a pseudocubic perovskite structure with grain sizes ranging from 0.1 to 0.5 μm， along with a small amount of pores. The submicron grain size contributes to enhanced optical transmittance. With increasing SLZ content， the transmittance gradually improves， reaching 45% at a wavelength of 2 000 nm in the infrared region. Within the frequency range of 10² ~2×10⁶ Hz， the dielectric constant exceeds 2 050 and the dielectric loss remains below 0.1， indicating good frequency stability. Impedance spectroscopy reveals a non-Debye relaxation behavior. The relaxation process at high temperature is mainly attributed to the short-range hopping of ionized oxygen vacancies. In the medium- and high-frequency regions， the temperature dependence of conductivity weakens， and the conduction mechanism transitions from long-range charge migration at low frequency to short-range hopping between localized states at high frequency.  Conclusions The excellent optoelectronic properties indicate that KNN-SLZ ceramics have promising applications in transparent electronic devices.

Key words: （K_0.5Na_0.5）NbO₃;lead-free transparent ceramics;electrical property;impedance analysis;dielectric constant