Baghdedi Dhouha, Dahri Asma, Tabellout Mohamed, Abdelmoula Najmeddine, Benzarti Zohra
Laboratory of Multifunctional Materials and Applications (LaMMA), Faculty of Sciences of Sfax, University of Sfax, BP 1171, Sfax 3000, Tunisia.
Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9, France.
Nanomaterials (Basel). 2025 Jun 12;15(12):918. doi: 10.3390/nano15120918.
Bismuth ferrite (BiFeO, BFO) is a promising multiferroic material, but its optoelectronic potential is limited by a wide bandgap and charge recombination. Here, we report the sol-gel synthesis of Co-doped BiFeO/BiFeO heterostructured nanopowders (x = 0.07, 0.15) alongside pristine BFO to explore Co doping and phase engineering as strategies to enhance their functional properties. Using X-ray diffraction (XRD) with Rietveld refinement, Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), UV-Vis spectroscopy, and dielectric analysis, we reveal a biphasic structure (rhombohedral R3c and cubic I23 phases) with tuned phase ratios (~73:27 for x = 0.07; ~76:24 for x = 0.15). Co doping induces lattice strain and oxygen vacancies, reducing the bandgap from 1.78 eV in BFO to 1.31 eV in BFO and boosting visible light absorption. Dielectric measurements show reduced permittivity and altered conduction, driven by [Co-V] defect dipoles. These synergistic modifications, including phase segregation, defect chemistry, and nanoscale morphology, significantly enhance optoelectronic performance, making these heterostructures compelling for photocatalytic and photovoltaic applications.
铋铁氧体（BiFeO₃，BFO）是一种很有前景的多铁性材料，但其光电潜力受到宽带隙和电荷复合的限制。在此，我们报告了与原始BFO一起通过溶胶-凝胶法合成Co掺杂的BiFeO₃/BiFeO₃异质结构纳米粉末（x = 0.07，0.15），以探索Co掺杂和相工程作为增强其功能特性的策略。通过使用带有Rietveld精修的X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、场发射扫描电子显微镜（FE-SEM）、紫外可见光谱和介电分析，我们揭示了一种双相结构（菱面体R3c相和立方I23相），其相比例经过调整（x = 0.07时约为73:27；x = 0.15时约为76:24）。Co掺杂会引起晶格应变和氧空位，使带隙从BFO中的1.78 eV降低到BFO₀.₀₇中的1.31 eV，并增强可见光吸收。介电测量表明，由[Co-V]缺陷偶极驱动，介电常数降低且传导发生改变。这些协同改性，包括相分离、缺陷化学和纳米级形态，显著提高了光电性能，使这些异质结构在光催化和光伏应用方面具有吸引力。
