In the process of exploring ferroelectric semiconductors, a new system of (1−x) KNbO₃–xSrFeO_3−δ (x = 0.00‐0.20) was successfully synthesized via solid‐state reaction. The crystal structures, ferroelectric, dielectric, optical, and electrical properties were systematically characterized. The orthorhombic phase with Amm2 space group is detected in all the ceramics. In addition, the orthorhombic and tetragonal phases coexist in 0.80KNbO₃‐0.20SrFeO_3‐δ ceramic. The decrease in oxygen octahedron distortion induces a weak ferroelectric polarization. The existence of long‐range ferroelectric polarization order in all the ceramics is verified and the bandgap of the ceramics can be tuned to ~2.18 eV. The improved short‐circuit photocurrent density (J_sc) and open‐circuit voltage (V_oc) of the poled 0.95KNbO₃‐0.05SrFeO_3−δ ceramic at 30 kV/cm are ~6.90 nA/cm² and 0.04 V, respectively. The activation energies for electrical conductivity of the grains and grain boundaries from 0.90KN–0.10SF ceramic are 0.67 and 0.77 eV, respectively, which indicate the doubly ionized oxygen vacancies. This work provides a new way to tune the optical bandgap/ferroelectric properties of KNbO₃‐based ceramics for potential application in ferroelectric photovoltaic and energy fields.

中文翻译：

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带隙窄的Sr / Fe改性KNbO3铁电半导体的晶体结构和电性能

在探索铁电半导体的过程中， 通过固相反应成功地合成了一个新的（1- x）KNbO ₃ – x SrFeO _3-d（x = 0.00-0.20）系统。系统地表征了晶体结构，铁电，介电，光学和电学性质。在所有陶瓷中都检测到具有Amm2空间群的斜方晶相。另外，正交相和正交相共存于0.80KNbO ₃ -0.20SrFeO3 _-δ中陶瓷制品。氧八面体畸变的减少引起弱的铁电极化。验证了所有陶瓷中都存在长距离铁电极化顺序，并且可以将陶瓷的带隙调整为〜2.18 eV。极化的0.95KNbO ₃ -0.05SrFeO3 _-δ陶瓷在30 kV / cm时的改善的短路光电流密度（J _sc）和开路电压（V _oc）为〜6.90 nA / cm ²和0.04 V分别。0.90KN–0.10SF陶瓷的晶粒和晶界的电导活化能分别为0.67和0.77 eV，表明双电离的氧空位。这项工作为调节基于KNbO ₃的陶瓷的光学带隙/铁电性能提供了一种新方法，可用于铁电光伏和能源领域。