Structure Of SrTiO3 Research Articles

Effect of La concentration on phase formation, local structure and optical properties of Sr1-xLaxTiO3 nanoparticles

The objective of this paper is to give information about phase formation, local structure and optical characteristics measured of the Sr1-xLaxTiO3 (x = 0–0.10; SLTO) nanoparticles. These nanoparticles have been synthesized by microwave-assisted sol-gel auto combustion method. Experimentally, the structural information was gathered by using the X-ray diffractometer and showed a pure phase with cubic perovskite structure of all samples. As well, the crystallite size and particle size of the SLTO samples decreased as the La doping content increased. The micro-strain (varying between 0.63×10−3 and 1.48×10−3) produced in the samples through Williamson-hall plot. The optical properties were determined using UV–Vis spectrophotometer. The band gap (Eg) was determined for all samples to be 4.10 eV. The study of local structure was performed by utilizing the synchrotron radiation X-ray absorption near edge structure (XANES) technique. The analyses XANES spectra clearly showed that the oxidation state of Sr, La and Ti ions are +2, +3 and + 4, respectively. The clear agreement between measured and calculated XANES spectra was the strongest evidence of La atoms occupies A-site (Sr) in SrTiO3 structure.

Anomalous resistive switching effect in La0.8Ca0.2MnO3/Nb:SrTiO3 structure

A barrier-type resistive switching (RS) unit, composed of a metal and Nb:SrTiO3 (NSTO), holds significant potential for data storage applications due to its high storage density, low operating voltage, and excellent stability. While extensive research has been conducted on conductive oxides (COs), there has been relatively less focus on the RS properties of heterogeneous structures combing CO electrodes and NSTO. Epitaxial growth of CO on NSTO is expected to yield devices with enhanced stability and repeatability. This study explores the RS characteristics of La0.8Ca0.2MnO3 (LCMO)/NSTO heterostructures through epitaxy of both conventional and anoxic LCMO films on (00 l)-oriented NSTO single crystal substrates. The results reveal that the conventional LCMO/NSTO structure exhibits a conventional counterclockwise bipolar RS (BRS) effect, while the anoxic LCMO/NSTO heterostructure demonstrates a unique clockwise (CW) BRS effect (exhibiting different RS characteristics under different applied voltages). The study concludes that the CW-BRS effect mechanism is attributed to a high concentration of oxygen vacancies (Vo) in LCMO. Under different external electric fields, Vo in LCMO and NSTO migrate to the LCMO/NSTO interface, respectively, leading to multiple changes in the interface barrier. These findings offer valuable experimental insights for utilizing CO in the field of RS applications.

Innovative dilute magnetic compositions for spin-electronics field: Room temperature ferromagnetism of Sr0.98Gd0.02Ti0.98X0.02O3 (X = Ru, Mn, Fe)

An interesting new dilute magnetic compositions have been synthesized by solid-state reaction composed of (Gd, Ru), (Gd, Mn) and (Gd, Fe) codoped SrTiO3 semiconductors. The X-ray diffraction (XRD) patterns of pure, (Gd, Ru), (Gd, Mn) and (Gd, Fe) codoped SrTiO3 samples verified the formation of cubic SrTiO3 structure. The morphological analysis using scanning electron microscope (SEM) showed that the addition of (Gd, Ru), (Gd, Mn) and (Gd, Fe) ions obviously effect on grains size and shape of SrTiO3 powder. The band gap energy of SrTiO3 powder was found to be 3.22 eV, and when (Gd, Ru), (Gd, Mn) and (Gd, Fe) ions incorporated into its lattice a blue shift to 3.28, 3.29 and 3.295 eV were detected, respectively. The X-ray photoelectron spectroscopy (XPS) analysis of (Gd, Mn) codoped SrTiO3 composition (best ferromagnetic sample) ruled out the presence of Gd and Mn metals and confirmed the existence of Gd3+ and Mn2+ oxidation states. The measured magnetic results indicated that (Gd, Ru), (Gd, Mn) and (Gd, Fe) dopants strongly advance the ferromagnetic nature of SrTiO3 structure. The H-M loop of (Gd, Mn) codoped SrTiO3 composition gives the best ferromagnetic order with detected saturation magnetization (MS), coercivity (HC) and retentivity (Mr) of 0.52 emu/g, 177 Oe and 0.054 emu/g, respectively. These outcomes established the promising room temperature ferromagnetic order of the fabricated compositions, especially Sr0.98Gd0.02Ti0.98Mn0.02O3 semiconductor for spin-electronics applications.

Modulating the electronic structure of macroporous SrTiO3 through cobalt doping for enhance photocatalytic hydrogen evolution

The modulation of electronic structure plays a crucial role in enhancing the adsorption of H* for photocatalytic hydrogen evolution. In this study, we prepared a three-dimensionally ordered macroporous structure of cobalt doping SrTiO3 (Co/3DOMSTO) to provide a large specific surface area that exposes more active sites. The prepared catalysts exhibited the highest rate of photocatalytic hydrogen evolution, reaching 5892.86 μmol g−1 h−1, along with an apparent quantum efficiency (AQE) of approximately 2.4% under illumination at 427 nm. Additionally, the introduction of metal cobalt helped to modulate the electronic structure of Co/3DOMSTO and facilitate spatial charge separation. X-ray absorption fine structure (XAFS) and density functional theory (DFT) calculations were conducted to demonstrate that cobalt occupied the Ti sites on the surface of 3DOMSTO, resulting in changes in the electronic distribution state within space. This phenomenon facilitates the enrichment of electrons at the adjacent Ti sites, making the charge-rich Ti a new active site. These findings underscore the pivotal role played by the geometric configuration and tailored electronic structure of 3DOMSTO in augmenting its photocatalytic performance.

New solvothermal flow synthesis of strontium titanate nanoparticles based on the use of acetylacetonate precursors in water/ethanol mixture

In this study, strontium titanate (SrTiO3) nanoparticles were obtained utilizing a one-step supercritical continuous solvothermal synthesis process involving acetylacetonate precursors for both strontium and titanium cations instead of the historical alkoxide ones. These precursors are expensive, difficult to access (especially for strontium isopropoxyde) and inadequately stable, forcing the use of a glove box and controlled atmospheres, which is not the case for acetylacetonates. Pure SrTiO3 nanoparticles with a crystallite size of roughly 20 nm were successfully synthesized. In addition to the cubic structure of SrTiO3, FTIR revealed surface functions that are typical of "wet" processes, while Raman spectroscopy showed the activation of non-centrosymmetric modes brought on by non-linear contributions. The nanoparticles show a faceted shape and are stable at elevated temperatures (up to 800 °C), according to in-situ high temperature XRD measurements. However, due to a chemical deficiency in strontium, titanium dioxide (TiO2) phases are formed at higher temperatures. In-situ high temperature HRTEM investigations showed the existence of two populations of particles, with a better stability for the bigger-sized particles after thermal treatment as well as the sintering and restructuring of the smallest ones. Also, the microscopy results suggest the possibility of a chemical inhomogeneity within the crystallites. Overall, this study offers important new knowledge on the physicochemical characteristics of the synthesized SrTiO3 nanoparticles and their thermal stability using a novel supercritical continuous solvothermal approach based on the use of acetylacetonate precursors.

Regular perovskite SrTiO3 and monoclinic layered perovskite Nd2Ti2O7 for oxidative coupling of methane: Elucidating the role of chemisorbed oxygen species and lattice oxygen

Herein, regular perovskite SrTiO3 and monoclinic layered perovskite Nd2Ti2O7 have been prepared by the sol-gel method and calcined at different temperatures. As the calcination temperature of SrTiO3 increases, the Ti element on their surface is enriched, and the amount of Sr element that provides basic sites is reduced, resulting in a decrease in the number of basic sites on the catalyst surface. For Nd2Ti2O7, its surface is enriched with Nd elements, but the enrichment amount does not change with the increase in calcination temperature, and it contains less surface basic sites less than SrTiO3. Although the enrichment of Ti on the surface of SrTiO3 is conducive to the formation of oxygen vacancies, the oxygen vacancies on the surface of Nd2Ti2O7 are more abundant than those on SrTiO3. The amount of electron-deficient oxygen species on their surfaces is influenced by the presence of basic sites, which make it more favorable to stabilize electrophilic oxygen species. The C2 selective oxygen species are chemisorbed oxygen (O2-, O2δ-, O22-) for SrTiO3 and surface lattice oxygen for Nd2Ti2O7. This is because the [TiO6] octahedra in the crystal structure of SrTiO3 are tightly stacked, whereas the [TiO6] units in the Nd2Ti2O7 structure are loosely stacked, resulting in a weaker Ti-O bond strength in Nd2Ti2O7 compared with SrTiO3. In addition, the lattice oxygen of SrTiO3 has strong basicity, which is beneficial for activating gas-phase oxygen to generate chemisorbed oxygen species and stabilizing them on the catalyst surface, while the nucleophilic lattice oxygen is more likely to cause deep oxidation of methane and coupling products. However, the and basicity of lattice oxygen in Nd2Ti2O7 are weaker than those in SrTiO3, making it more favorable for C2 selectivity.

Achieving Visible Light Triggered Overall Water Splitting over Plasmonic Au/SrTiO3:Al Photocatalyst

AbstractThe surface plasmon resonance (SPR) effect has garnered extensive attention in semiconductor photocatalysis for solar energy conversion, thanks to its remarkable optical properties. However, the majority SPR‐induced photocatalytic systems have been limited to achieving hydrogen evolution or oxygen evolution half reactions, and attaining overall water splitting on a SPR‐induced photocatalyst under visible light remains a formidable challenging. In this study, we employed a plasmonic photocatalyst Au/SrTiO3, and further enhanced its performance by doping aluminum (Al) into the SrTiO3 lattice (denoted as Au/SrTiO3:Al). By constructing reduction cocatalyst (RhCrOx) and oxidation cocatalyst (CoOOH), the Au/SrTiO3:Al photocatalyst successfully realizes photocatalytic overall water splitting with a stoichiometric ratio of H2 and O2 under visible light (λ≥440 nm). We revealed that the introduction of Al species effectively modified the electronic structure of SrTiO3, thereby enhancing the hydrogen evolution reaction in Au/SrTiO3:Al. Simultaneously, the RhCrOx and CoOOH cocatalysts synergistically capitalized on the short‐lived hot electrons and holes generated by the plasmonic Au/SrTiO3:Al photocatalyst, enabling to realize photocatalytic overall water splitting. This work offers a promising avenue for the rational design of plasmon‐induced overall water splitting photocatalysts through the integration of suitable cocatalysts and surface/interface engineering strategies.

Enhancement of SrTiO3 photocatalytic efficiency by Al doping: Answers from the structure, morphology and electronic properties contributions

Our study focuses on disclosing the mechanisms standing behind the improved photocatalytic performance of SrTiO3, where Al modification of the perovskite structure boosts the photocatalytic O2 evolution activity of the Al:SrTiO3 system. By adapting the synthesis method that produces well-crystallized materials with low defect density and employing surface modification techniques, we aim to enhance the photocatalytic efficiency of SrTiO3via Al2O3 nanoceramic oxide doping at concentrations ranging from 0 to 10% and further examining of the relationship between doping process and the changes in the electronic and crystalline structure of SrTiO3. The prepared Al-based SrTiO3 perovskite samples (Al3%:SrTiO3, Al7%:SrTiO3, Al10%:SrTiO3) were thoroughly characterized to understand their structural, electronic, and morphological properties. Complementary X-ray techniques were employed to assess the stoichiometry (X-ray photoelectron spectroscopy - XPS), local environment, and chemical state (X-ray absorption spectroscopy - XAS in both total electron yield (TEY) and fluorescence yield (TFY). The comprehensive characterization enables us to understand the changes in the electronic properties and morphological features of the modified samples elucidating the surface formation mechanism while providing insights into the structural modifications induced by Al doping in the SrTiO3 perovskite lattice. Our findings give new perspectives for the development of Al-modified SrTiO3 perovskite materials with enhanced photocatalytic performance providing rich insights into the optimization of photocatalytic processes for applications in environmental remediation and sustainable energy production.

Investigation of doping effect on the local structure and photocatalytic activity of SrTiO3

Investigation of doping effect on the local structure and photocatalytic activity of SrTiO3

Theoretical exploration of CO2 photocatalytic reduction using single atom gold nanoparticles (Au0) modified SrTi0.875Hf0.125O3

As a promising photocatalytic CO2 reduction material, SrTiO3(STO) still faces many drawbacks. In order to further improve its photocatalytic efficiency, this article explores the changes in the structure, optics, electronics, and interface properties of STO by doping 12.5 % Hf and attaching varying degrees of Au nanoparticles on its surface. Doping Hf can improve structural stability and reduce the activation energy of photocatalytic CO2 to CH4. On this basis, adsorbing different amounts of Au nanoparticles will form Schottky barriers and built-in electric fields at the interface, improving the migration and light absorption performance of charge carriers and thus increasing the CO2 reduction reaction (CO2RR) yield. The characterization methods of catalysis and interface performance indicate that when 4Au nanoparticles are adsorbed, the rate determining step for photocatalytic CO2 reduction to CO can be significantly reduced. This is due to the dual track hybrid nature of the adsorbed state, which can significantly reduce the reaction potential barrier.

The fluctuated structural/electronic properties of SrTiO3 two-dimensional materials caused by surface effects

Perovskite oxide thin films have many astonishing properties, such as multiferroicity, superconductivity, strong correlation, etc, and are closely related to orientations with different symmetry and structural characteristics. Recently, perovskite oxide films with only one unit cell thickness have been synthesized successfully (Ji et al 2019 Nature 570 87–90). Here we investigated the structure and electronic properties of SrTiO3 (STO) two-dimensional (2D) materials with (001), (110), and (111) surfaces. We found that due to surface effects caused atomic distortion fluctuations, the lattice constant and thickness of STO 2D materials with the (110) surface fluctuate sharply with the increase of atomic layers. The band gap of STO 2D materials exhibits oscillation as the number of atomic layers increases, due to the different atomic distortion and surface reconstruction with odd and even atomic layers. The STO 2D materials along (001) surfaces with different atomic layers are always semiconductors. As the atomic layers increasing, the electronic structure of STO 2D materials with (110) or (111) surfaces continuously transitioning between semiconductor and metallic phases, and finally totally become metallic phases, which is closely related to the surface reconstruction effect. The differences between STO 2D materials along the (001) and (110) or (111) surfaces are significant and can be explained by mixed Sr-d, Ti-d, and O-p orbitals. Our studies may provide new insights into the surface effects of perovskite oxide 2D materials.

First principles study of the role of C in tuning the band gap of Al, Si-doped SrTiO3 to enhance photocatalytic activity

This work demonstrates that C-assisted Al, Si-doping can effectively regulate the band structure of SrTiO3 for improving photocatalytic activity. The effects of (Al + C) and (Si + C) co-doping on electronic structure and optical properties of SrTiO3 are performed by first-principles calculations. It is found that the auxiliary effect of the C element on the two doped systems is different. The (Al + C) co-doping effectively passivates the impurity band in the Al mono-doping case, which leads to the expansion of the band gap. On the contrary, the (Si + C) co-doping induces an impurity band near the top of the valence band and narrows the gap, which is ascribed to the strong coupling between C and O atoms. The calculated light absorption curves imply that (Al + C) and (Si + C) co-doping are effective ways to expand the light response region. The further analysis of band edge alignments of both the two co-doped systems indicates that (Si + C) co-doped SrTiO3 is more favorable for water splitting.

Lattice distortion-driven band gap engineering and enhanced electrocatalytic activity of Mn-substituted nanostructured SrTiO3 materials: A comprehensive investigation

The lattice distortion and electrocatalytic activity are investigated by the mono-substituent of Mn with different concentrations to generate localized states in the electronic structure of SrTiO3. The sol-gel approach has been employed to fabricate SrTiO3 and SrTi1-xMnxO3 nanostructures (NSs). The structural analysis indicates Mn incorporation into Ti sites of SrTiO3, which shifts the lattice towards a higher diffraction angle with a single-phase cubic structure. The optical absorption spectra exhibit a decrease in band gap from 3.27 to 1.89 eV and reveal the shift in band edge positions towards the visible region. XPS analysis is carried out to confirm the formation of oxygen vacancies and valence band edge position. For SrTi0.88Mn0.12O3, OER and HER have the overpotential of 445 and 157 mV at a current density of 100 and 10 mA cm−2. Hence, the substitution of Mn (x = 0.12) into SrTiO3 lattice results in lattice distortion that enhances the electrochemical performance compared to SrTiO3. The current work manifestly established the optimal Mn composition (x = 0.12) in SrTiO3 lattice as desirable materials with defective valence states for required electrocatalytic redox potential as well as the acceleration of charge transfer kinetics towards water splitting applications.

Properties of cobalt-doped SrTiO3 derived from two methods: the modified Pechini method and the citrate combustion method

Two wet-synthesis methods: citrate-combustion and modified (with PVA addition) Pechini synthesis were used to obtain Co-doped strontium titanate with assumed chemical compositions of SrTi1−xCoxO3 (where x = 0.02; 0.06; 0.10). All samples were calcined at 900 °C and sintered at 1200 °C, with PVA series being also calcined at 700 and 800 °C, since TG measurements indicated for this method materials lower minimal calcination temperature than for the citrate-combustion series materials. In general, the modified Pechini approach lowers calcination temperature of materials (up to 200 °C) and produces more structurally homogeneous materials than in the case of the citrate-combustion methods. However, the HT XRD measurements reveal the presence of extra cobalt oxide phases in pva_STO_xCo materials that were not visible using conventional XRD measurements. The presence of cobalt oxide has been confirmed for both series of materials based on TPR tests. Moreover, these measurements indicate the incorporation of some amount of cobalt into the perovskite structure. The fact of substituting titanium with cobalt in SrTiO3 structure seems to be confirmed by the results of XAS studies. Additionally, XAS results allowed us to state that Co2+/Co3+ ratio fell as cobalt loading increased in the materials. The examination of SrTiO3 lattice parameter changes for sintered samples is consistent with the findings of the XAS tests and indicates that cobalt adopts +2 oxidation state in the case of the material with the lowest Co content, and the share of Co3+ increases with the growth of the Co amount introduced into the system.

Development of a biosensor based on a surface plasmon resonance structure comprising strontium titanate, graphene and affinity layers for malaria diagnosis

This paper investigates the numerical analysis of a highly performed surface plasmon resonance (SPRE)-based sensor employing a hybrid structure of SrTiO3 (STO) and graphene for rapid detection of malaria. The investigation is performed using the angular interrogation technique and transfer matrix method. The SPRE device has a glass prism, silver (Ag), STO, graphene, affinity layer and sensing medium (SGM). Four coupling prisms are examined and we found the prism N-FK51A corresponds to the highest sensitivity. The sensitivity of the structure N-FK51A/Ag/STO/graphene/affinity layer/SGM is found to be 205.405, 222.222 and [Formula: see text]/RIU for Schizont, Trophozoite and Ring malaria stages. The layer thicknesses are then optimized and it is found that the proposed SPRE sensor can achieve a sensitivity of 278.378, 227.027 and [Formula: see text]/RIU for Schizont, Trophozoite and Ring malaria stages with 30 nm (silver), 1[Formula: see text]nm (STO), mono-sheet of graphene and 5[Formula: see text]nm of the affinity layer. These findings demonstrate that the proposed method and structure can be used efficiently for biomedical applications.

Influence of the molten SrCl2 treatment on the surface structure and photochemical reactivities of SrTiO3

Al-doped SrTiO3 synthesized in a SrCl2 melt is among the most efficient known photocatalysts for water splitting. Although the effect of Al3+ incorporation has been widely discussed, the role of the molten SrCl2 remains unclear. Herein, we report the influence of the molten SrCl2 treatment and a comparable molten KCl treatment on the surface structure and composition of SrTiO3 using AFM and XPS. The hydrogen evolution rates of particulate Al-doped SrTiO3 photocatalysts were measured with a parallelized and automated photochemical reactor. In SrCl2, it is found that 3 % to 5 % of the SrTiO3 dissolves in the melt, revealing a new hydroxyl-rich surface. The melt reacts with the alumina crucible to form Sr3Al2O6, ultimately leading to the elimination of the melt. In addition, the surface potential difference between (100) and (110) surfaces increases from 0.07 V to 0.21 V after the treatment, allowing for enhanced separation of photogenerated charge carriers and leading to improved photocatalytic reactivity. When heated in KCl, the SrTiO3 surfaces reconstruct and this changes the spatial distribution of photocathodic and photoanodic reaction sites.

Defect-induced Sr1−xPrxTiO3 crystallites by burial sintering and its optoelectronic applications

The band structure of SrTiO3 was altered by introducing Pr3+ in the Sr2+ site and subsequent graphite burial sintering. The asymmetric nature of the (310) peak in XRD and the emergence of Eg and B1g modes in the Raman spectrum suggest the transformation from cubic to tetragonal phase for the Sr1-xPrxTiO3 system with x ≥ 0.1. The development of the forbidden first-order Raman peaks and novel spectral properties are attributed to the local vibrational modes linked to oxygen vacancies. Structural variations in terms of lattice strain were investigated using a W–H plot, and morphological changes were analyzed by high-resolution FE-SEM. High infrared absorption in UV–Vis–NIR spectra and a significant reduction in band gap from 2.8 eV to 1.8 eV were accomplished through increased disorder in the lattice and the reduction of Ti4+. The blue shift in absorption spectra with Pr concentration can be used to tune the absorption range for sensing purposes. The formation of new electronic states observed here offers a novel approach for band gap modification in perovskites for photocatalytic and photovoltaic applications.

Strong Ferromagnetic Manipulation of SrTiO3 from CO2 -Straining Effect on Electronic Structure Modulation.

2D magnetic materials are ideal to fabricate magneto-optical, magneto-electric, and data storage devices, which are proposed to be critical to the next generation of information technologies. Benefited from their labile structures, 2D perovskites are amenable for magnetic manipulation through structural optimization. In this work, 2D room-temperature ferromagnetic SrTiO3 is achieved through straining effect induced by supercritical carbon dioxide (SC CO2 ). According to experimental results, the cubic phase of SrTiO3 is converted to tetragonal with exposure of (110), (200), (111), and (211) planes over the SC CO2 treatment, leading to significant ferromagnetic enhancement. Theoretical calculations illustrate that over the conversion from cubic to tetragonal, the electronic structure of SrTiO3 is significantly modulated. Specifically, the spin density of planes of (200), (111), and (211) is enhanced, presumably due to the stabilization of the highest occupied molecular orbital over straining by SC CO2 , leading to magnetic optimizations. This work suggests that magnetic optimization can be achieved from SC CO2 -induced electronic structure modulation.

Density Functional Characterization of Electronic and Optical Properties of Strontium Titanate Under Doping and Strain for Optoelectronic Applications

We perform first-principles calculations, to investigate the effect of doping of metal dopants (silver, gold, aluminum, and copper) on the electronic, structural, and optical properties of strontium titanate SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . We further explore the impact of varying strains (compressive and tensile) on the optical and electronic properties of pristine and doped SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . Our results suggest that the undoped SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> exhibit a wide bandgap of 2.94 eV with high optical absorption only in the ultraviolet (UV) region. On doping the SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> by metal dopants, the bandgap is significantly narrowed and most of the absorption peaks are found to shift towards the lower energies (red-shift). Subsequently, the absorption is enhanced in the visible region (∼380 to 800 nm) of the optical spectrum. The decrease in the bandgap is highest for the dopant Cu. Further, on the application of the biaxial strain (tensile and compressive) on the doped-SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , the optical absorption is enhanced in the visible region, particularly for the high compressive strain of 20%. The calculated refractive index and dielectric function for all the structures of SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> are found to follow the trend of absorption. The enhanced absorption in the desired visible region through doping and strain may find prospective applications in the fabrication of photovoltaic, optoelectronic, and solar devices.

Suppression of intrinsic thermal conductivity in Sr1-x Gd x TiO3 ceramics via phonon-point defect scattering for enhanced thermoelectric application.

A substantial reduction in the thermal conductivity for strontium titanate (ABO3) perovskite structure was realized for the A-site substitution of gadolinium (rare earth element) in SrTiO3 ceramics. The effect of Gd3+ substitution on the structure, composition, and thermoelectric properties of SrTiO3 was investigated. The substitution of Gd3+ in the SrTiO3 matrix resulted in the minimalization of thermal conductivity. The thermal conductivity followed a similar trend as that of thermal diffusivity, but specific heat capacity exhibited a non-monotonic trend. The thermal conductivity is reduced to 1.05 W m-1 K-1 for the minimal substitutional composition (Sr0.99Gd0.01TiO3) which is 30% less than that of SrTiO3 at 303 K. The variation in the ionic radii and atomic mass of the heavier rare earth Gd3+ substituted over Sr2+ resulted in the reduction of thermal conductivity of SGTO ceramics caused by the corresponding boundary scattering at low temperatures and temperature-independent phonon-impurity scattering at high temperatures.