This article focusses on the detailed structural and optical properties of ‘Eu’ and ‘Ni’ co-substituted Bismuth Ferrite nanoparticles synthesized using the sol-gel method. Raman analysis have confirmed the substitution induced structural distortion leading to the co-existence of Rhombohedral and Orthorhombic structures supporting the XRD and Rietveld Refinement results. Morphological studies using FESEM and HRTEM have shown irregular and inhomogeneous distribution of particles with presence of mixed phases and the elemental composition is also confirmed through EDAX analysis. The XPS analysis indicated the simultaneous presence of Fe²⁺and Fe³⁺states along with Bi³⁺, Eu³⁺ and oxygen vacancies. Thorough optical investigation using UV-Vis and PL Spectroscopy has shown an increase in absorption intensity in the visible region with a bandgap tuning from 2.17 eV to 2.12 eV in the co-substituted nanoparticles. A possible schematic energy band diagram is proposed on the basis of observed transitions in photoluminescence studies, VB-XPS analysis along with the knowledge of optical transitions in d⁵ systems. Photocatalytic performance of the synthesized nanostructures is studied by degradation of 2-nitrophenol. The enhanced photocatalytic response has been explained on the basis of decreased band-gap, space charge thickness and charge carrier recombination.

本文重点介绍使用溶胶-凝胶法合成的“ Eu”和“ Ni”共取代铋铁氧体铋纳米粒子的详细结构和光学性质。拉曼分析已经证实了取代引起的结构变形，从而导致支持XRD和Rietveld精炼结果的菱面体和正交晶结构共存。使用FESEM和HRTEM进行的形态学研究表明，存在混合相的颗粒分布不规则且不均匀，并且通过EDAX分析也证实了元素组成。XPS分析表明同时存在Fe ²⁺和Fe ³⁺态以及Bi ³⁺，Eu ³⁺和氧气的空缺。使用UV-Vis和PL光谱进行的彻底光学研究表明，在共取代的纳米粒子中，带隙从2.17 eV调节到2.12 eV时，可见光区域的吸收强度增加。根据在光致发光研究中观察到的跃迁，VB-XPS分析以及d ⁵系统中的光跃迁知识，提出了可能的示意性能带图。通过降解2-硝基苯酚研究了合成的纳米结构的光催化性能。基于减小的带隙，空间电荷厚度和电荷载流子复合已经解释了增强的光催化响应。