Reducing bandgap energy in ferroelectric materials has become an important commitment to improve the performance of the photovoltaic solar cell. This study reports the effect of the transition metals Co and Fe ions co-doping on the structure and bandgap of neodymium-modified Bi 4 Ti 3 O 12 based oxide. The quantitative structural analyses by XRD confirms well-crystallized samples with orthorhombic crystal structure based on B2cb space group. Optical properties were measured by a UV–vis spectrometer. The oxygen vacancies presence and the Fe and Co valence states estimation were carried out by electron spin resonance. The incorporation of Co and Fe ions into Bi 3.25 Nd 0.75 Ti 3 O 12 significantly modified the bandgap structure, promoting a red-shift and lower energies absorption which was related to the changes in tilting angles, bond lengths, octahedral distortions and oxygen vacancies formation, still maintaining ...

中文翻译：

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八面体畸变和氧空位引起带隙变窄，并增强了Co / Fe共掺杂的Bi 3.25 Nd 0.75 Ti 3 O 12铁电体在光伏应用中的吸收率

降低铁电材料中的带隙能量已经成为改善光伏太阳能电池性能的重要承诺。这项研究报告了过渡金属Co和Fe离子共掺杂对钕改性Bi 4 Ti 3 O 12基氧化物的结构和带隙的影响。XRD的定量结构分析证实了基于B2cb空间群的正交晶结构的良好结晶样品。光学性质通过紫外可见光谱仪测量。通过电子自旋共振进行氧空位的存在以及Fe和Co价态的估计。Co和Fe离子掺入Bi 3.25 Nd 0.75 Ti 3 O 12中可以显着改变带隙结构，从而促进红移和较低的能量吸收，这与倾斜角，键长，