Abstract The crystal structure of (1-x)KNbO3–xBiFeO3 (KNBF) and (1-x)KNbO3-LaFeO3 (KNLF) (where x = 0.00; 0.01; 0.02; 0.04; 0.08; 0.16; 0.32) was evaluated by XRD and Raman spectroscopy. XRD data show the crystal symmetry to evolve from orthorhombic to tetragonal with increasing x. The optical bandgap was found to narrow systematically with increasing x. Raman spectroscopy analysis corroborated long-range polar order in all compositions. The photoresponse of x = 0.32 shows a typical diode–like behaviour, with current and voltage of 0.115 µA and 0.075 V for KNBF and 0.19 µA and 0.035 V for KNLF, respectively. To our knowledge these represent the largest values among KNbO3–based ceramics, making them promising for photovoltaic applications.

中文翻译：

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KNbO 3 – AFeO 3 (A = Bi 3+ 或La 3+ )陶瓷的光响应及其与带隙变窄的关系

摘要 (1-x)KNbO3-xBiFeO3 (KNBF) 和 (1-x)KNbO3-LaFeO3 (KNLF)（其中 x = 0.00；0.01；0.02；0.04；0.08；0.16；0.32）的晶体结构通过 XRD 进行评估和拉曼光谱。XRD 数据显示晶体对称性随着 x 的增加从斜方晶演变为四方晶。发现光学带隙随着 x 的增加而系统地变窄。拉曼光谱分析证实了所有成分的长程极性顺序。x = 0.32 的光响应显示出典型的类似二极管的行为，KNBF 的电流和电压分别为 0.115 µA 和 0.075 V，KNLF 的电流和电压分别为 0.19 µA 和 0.035 V。据我们所知，这些代表了 KNbO3 基陶瓷中最大的价值，使它们有希望用于光伏应用。