This study aims to investigate the effect of iron doping on the structural, optical, dielectric and electrical properties of strontium titanate (SrTiO3 nanoceramics, with a view towards enhancing its potential for advanced multifunctional applications. For the preparation of the compounds having the formula SrFexTi1−xO3 (x = 0, 0.05, 0.1, and 0.15), iron is added to SrTiO3 at different concentrations (5%, 10%, and 15%). Using several approaches, such as X-Ray diffraction (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), UV–Visible spectroscopy, and Impedance Spectroscopy, the structural, optical, dielectric and electrical traits of the manufactured materials are carefully analysed. The formation of cubic SrTiO3 crystals in all samples is confirmed by XRD analysis. HRTEM studies verifies that the particle size increases as the Fe concentration increases. EDS and XPS further supported iron doping in strontium titanate, showing that iron ions have been effectively incorporated into the SrTiO3. A significant shift in the optical properties of strontium titanate is observed with Fe doping. While the UV–Vis–NIR absorption spectrum of pure strontium titanate showed absorption confined to the ultraviolet region (200–420 nm), the Fe-doped strontium titanate exhibited significantly enhanced absorption extending across the entire UV–Vis–NIR range (200–2000 nm). The optical band gap from lowered from 3.17 eV for undoped SrTiO3 to 2.02 eV for the 15% iron-doped sample. Fe ions may be involved in electron absorption and charge carrier recombination in the doped samples, as evidenced by the photoluminescence (PL) spectra, which show a drop in intensity with Fe doping. Fe doping led to a pronounced improvement in the functional properties of strontium titanate, with electrical conductivity increases from 3.8615 × 10–4 Sm−1 for pure strontium titanate to 8.0712 × 10–3 Sm−1 for 15% Fe-doped strontium titanate and the dielectric constant rises from 5.74 for pure strontium titanate to 19.34 for 15% Fe-doped strontium titanate at 1 MHz and at room temperature, indicating a substantial enhancement in charge transport and dielectric response due to Fe incorporation. The frequency-dependent conductivity behaviour follows Jonscher’s universal power law. By lowering the activation energy, iron improves charge transfer, according to Arrhenius plots. Likewise, iron inclusion reduces the overall impedance and enhances electrical conductivity in strontium titanate, according to impedance spectroscopy. These improvements in material performance achieved through Fe doping expand the potential of strontium titanate for diverse applications.

Fe-dopinginduced optical, electrical, and dielectric property enhancement in strontium titanate

期刊论文
发表日期：

2025年8月11日

查看全文

Rini Varghese,
Steffy Maria Jose,
J. K. Thomas,
Sibi C. Babu

摘要

This study aims to investigate the effect of iron doping on the structural, optical, dielectric and electrical properties of strontium titanate (SrTiO₃ nanoceramics, with a view towards enhancing its potential for advanced multifunctional applications. For the preparation of the compounds having the formula SrFe_xTi_1−xO₃ (x = 0, 0.05, 0.1, and 0.15), iron is added to SrTiO₃ at different concentrations (5%, 10%, and 15%). Using several approaches, such as X-Ray diffraction (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), UV–Visible spectroscopy, and Impedance Spectroscopy, the structural, optical, dielectric and electrical traits of the manufactured materials are carefully analysed. The formation of cubic SrTiO₃ crystals in all samples is confirmed by XRD analysis. HRTEM studies verifies that the particle size increases as the Fe concentration increases. EDS and XPS further supported iron doping in strontium titanate, showing that iron ions have been effectively incorporated into the SrTiO₃. A significant shift in the optical properties of strontium titanate is observed with Fe doping. While the UV–Vis–NIR absorption spectrum of pure strontium titanate showed absorption confined to the ultraviolet region (200–420 nm), the Fe-doped strontium titanate exhibited significantly enhanced absorption extending across the entire UV–Vis–NIR range (200–2000 nm). The optical band gap from lowered from 3.17 eV for undoped SrTiO₃ to 2.02 eV for the 15% iron-doped sample. Fe ions may be involved in electron absorption and charge carrier recombination in the doped samples, as evidenced by the photoluminescence (PL) spectra, which show a drop in intensity with Fe doping. Fe doping led to a pronounced improvement in the functional properties of strontium titanate, with electrical conductivity increases from 3.8615 × 10^–4 Sm⁻¹ for pure strontium titanate to 8.0712 × 10^–3 Sm⁻¹ for 15% Fe-doped strontium titanate and the dielectric constant rises from 5.74 for pure strontium titanate to 19.34 for 15% Fe-doped strontium titanate at 1 MHz and at room temperature, indicating a substantial enhancement in charge transport and dielectric response due to Fe incorporation. The frequency-dependent conductivity behaviour follows Jonscher’s universal power law. By lowering the activation energy, iron improves charge transfer, according to Arrhenius plots. Likewise, iron inclusion reduces the overall impedance and enhances electrical conductivity in strontium titanate, according to impedance spectroscopy. These improvements in material performance achieved through Fe doping expand the potential of strontium titanate for diverse applications.