Abstract This paper presents the electronic structure and optical behavior of Sn1-xFexO2 (0 % ≤ x ≤ 7 %) nanoparticles synthesized using co-precipitation assisted hydrothermal method. The structural properties of as-synthesized nanoparticles were examined using XRD and Raman spectroscopy. The XRD results demonstrated that all the samples are crystallized in tetragonal (rutile) crystal structure without any hint of impurity phase. The crystallite sizes measured using XRD spectra were found to vary from 7.0 to 10.0 nm. The effect of Fe doping and local defects were identified via surface-enhanced Raman spectroscopy (SERS). The local electronic structure was studied using NEXAFS at Fe L3, 2, O K edges which demonstrate that Fe ions are situated at the Sn sites with Fe3+ (pre-dominant) and Fe2+ (minor) mixed valance states. The octahedral (Oh) ligand field split the Fe (3d) state into t2g and eg states with ∼ 3 eV energy splitting. The optical properties were explored by using UV–vis spectra, which reveals transparent behavior in the visible light region and good absorption in the ultraviolet range. The asymmetrical change in the bandgap energy (3.6–3.1 eV) with the variation in Fe dopant level may be due to the casual distribution of Fe ions inside the host SnO2 crystal texture.

中文翻译：

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调整 Fe：SnO2 纳米粒子的结构、电子结构和光学特性

摘要 本文介绍了使用共沉淀辅助水热法合成的 Sn1-xFexO2 (0 % ≤ x ≤ 7 %) 纳米粒子的电子结构和光学行为。使用 XRD 和拉曼光谱检查合成纳米粒子的结构特性。XRD 结果表明所有样品均以四方（金红石）晶体结构结晶，没有任何杂质相。发现使用 XRD 光谱测量的微晶尺寸在 7.0 到 10.0 nm 之间变化。通过表面增强拉曼光谱 (SERS) 确定了 Fe 掺杂和局部缺陷的影响。在 Fe L3, 2, OK 边缘使用 NEXAFS 研究了局部电子结构，这表明 Fe 离子位于具有 Fe3+（主要）和 Fe2+（次要）混合价态的 Sn 位点。八面体 (Oh) 配体场将 Fe (3d) 态分裂为 t2g 和 eg 态，能量分裂约为 3 eV。通过使用紫外-可见光谱探索了光学特性，该光谱揭示了可见光区域的透明行为和紫外区域的良好吸收。带隙能量 (3.6-3.1 eV) 随 Fe 掺杂水平变化的不对称变化可能是由于主体 SnO2 晶体结构内 Fe 离子的随意分布。