Bulk Polycrystalline Materials Research Articles

Enhanced thermoelectric properties of Se-doped quasi-one-dimensional van der Waals crystal Ta2PdS6

Recently, quasi-one-dimensional van der Waals crystal Ta2PdS6 has been reported as a promising thermoelectric material with an extraordinarily high power factor. However, element doping to tune the thermoelectric properties has not been studied yet. Here, we systematically investigated the effect of Se doping on the phase composition, charge transport properties and thermoelectric performance of Se-doped Ta2Pd(S1−xSex)6 (x = 0, 0.02, 0.05, and 0.07) polycrystalline bulk materials. Upon doping Se at the S sites to increase the carrier concentration and mobility, the electrical conductivity of Ta2Pd(S0.93Se0.07)6 is dramatically enhanced, while the S is slightly reduced, yielding a significantly improved power factor compared to that of pristine Ta2PdS6. Consequently, Ta2Pd(S0.93Se0.07)6 exhibits a peak ZT of 0.29 at 700 K when the doping content x = 0.07, which is more than twice that of pristine Ta2PdS6.

Influence of Sputtering Power on the Properties of Magnetron Sputtered Tin Selenide Films.

The ecofriendly tin selenide (SnSe) is expected to find multiple applications in optoelectronic, photovoltaic, and thermoelectric systems. This work is focused on the thermoelectric properties of thin films. SnSe single crystals exhibit excellent thermoelectric properties, but it is not so in the case of polycrystalline bulk materials. The investigations were motivated by the fact that nanostructuring may lead to an improvement in thermoelectric efficiency, which is evaluated through a dimensionless figure of merit, ZT = S2 σ T/λ, where S is the Seebeck coefficient (V/K), σ is the electrical conductivity (S/m), λ is the thermal conductivity (W/mK), and T is the absolute temperature (K). The main objective of this work was to obtain SnSe films via magnetron sputtering of a single target. Instead of common radiofrequency (RF) magnetron sputtering with a high voltage alternating current (AC) power source, a modified direct current (DC) power supply was employed. This technique in the classical version is not suitable for sputtering targets with relatively low thermal and electrical conductivity, such as SnSe. The proposed solution enabled stable sputtering of this target without detrimental cracking and arcing and resulted in high-quality polycrystalline SnSe films with unprecedented high values of ZT equal to 0.5 at a relatively low temperature of 530 K. All parameters included in ZT were measured in one setup, i.e., Linseis Thin Film Analyzer (TFA). The SnSe films were deposited at sputtering powers of 120, 140, and 170 W. They had the same orthorhombic structure, as determined by X-ray diffraction (XRD), but the thickness and microstructure examined by scanning electron microscopy (SEM) were dependent on the sputtering power. It was demonstrated that thermoelectric efficiency improved with increasing sputtering power and stable values were attained after two heating-cooling cycles. This research additionally provides further insights into the DC sputtering process and opens up new possibilities for magnetron sputtering technology.

Unveiling the geometrical and mechanical properties of Σ3 (111) grain boundaries in Ni-based alloys: From interfacial insights

Understanding the properties of interfaces and grain boundaries is pivotal for advancing the design and performance of modern materials and devices. The mechanical strength and durability of materials are significantly influenced by the integrity of these interfaces and grain boundaries. In this study, we employ density functional theory calculations to investigate the geometries, electronic properties, and mechanical behaviors of Σ3 (111) grain boundaries in Ni, AlNi3, and FeNi3 systems. Result reveals that these grain boundaries exhibit trigonal, hexagonal, and hexagonal close-packed structures with minimal bond length distortions, attributed to specific misorientation angles of 60°. They also demonstrate bonding characteristics akin to their corresponding polycrystalline bulk materials, indicating stability and twist character with anti-phase boundaries. Evaluation of grain boundary energetics indicates low energy values and stability across the studied systems. Furthermore, we conduct a detailed examination of the interfacial grain boundary structures of Σ3 (111) Ni/AlNi3 and Σ3 (111) Ni/FeNi3, revealing trigonal closed space configurations with twist character and anti-phase boundaries. Electron localization in interfacial regions suggests a metallic nature of interfacial bonds, supported by density of state calculations and positive Cauchy pressure. Assessment of mechanical properties indicate ductile behavior due to structural heterogeneity, moderate anisotropy. Overall, present study underscores the enhanced mechanical properties resulting from heterogeneity, offering promise for future applications in advanced materials and devices. Additionally, a comparative analysis with highlights the advancements and contributions of this study to the existing body of knowledge.

In-situ rapid nondestructive characterization of multiple irregular three-dimensional grain boundary structures and electrical properties by nanorobot with SEM in ZnO

To address the problem of spatial quantification of irregular grain boundaries, a unique approach for the nondestructive characterization of multiple irregular three-dimensional grain boundaries is proposed using nanorobots with scanning electron microscopy (SEM) to accomplish in-situ rapid synchronized quantification of structures and electrical properties. By constructing a three-dimensional trigonometric geometric mapping relationship, multiple irregular three-dimensional grain boundary structures and electrical properties can be rapidly quantified. Experimental results demonstrate that it is feasible to accomplish in-situ rapid nondestructive characterizations. The two-dimensional profile shapes of the targeted grain boundaries at each layer exhibit irregular and non-uniform features in the Y-Z plane. The hypotenuse length between the virtual space tilting lines presents a three-dimensional characteristic in the X-Z plane. The spatial tilt angle of the virtual space tilting line can be calculated using the right-triangle relation. The unequal numbers of grains along the same tilted hypotenuse direction with equal lengths directly illustrate the existence of irregular and nonlinear grain boundaries in bulk ZnO ceramics. The relatively uniform spatial sizes of the grain boundary illustrate the coupled spatial characteristics existing in the irregular micro-structures. The relatively uniform equivalent circuit fitting parameters confirm the existence of relatively uniform doping components in bulk ZnO ceramics. Furthermore, this method provides a unique approach for the rapid nondestructive quantitative analysis of multiple three-dimensional irregular grain boundaries in bulk polycrystalline materials.

Argon Plasma Bombardment Induces Surface‐Rich Sn Vacancy Defects to Enhance the Thermoelectric Performance of Polycrystalline SnSe

AbstractNanoscale defects can induce the effective modulation of carrier concentration, mobility, and phonon scattering to secure high thermoelectric performance in semiconductors. However, it is still limited to effectively controlling nanoscale defects in thermoelectric materials. Here, argon plasma bombardment is employed to introduce a large number of point defects and dislocations in microcrystalline SnSe powders, synthesized by a solvothermal method. After sintering these powders into polycrystalline bulk materials, bulk SnSe shows the ZT increasing by up to 66.7% (from 0.36 to 0.6 at 773 K). Through detailed micro/nanostructure characterizations and first‐principles calculations, the underlying mechanism is elucidated for the evaluation of thermoelectric performance. This work provides a deep understanding of the mechanism of nanoscale defects in modulating thermoelectric performance and presents experimental evidence and experience for the design and synthesis of efficient thermoelectric materials, making significant contributions to future green energy technologies.

Exceptional Thermoelectric Performance of Cu2(Zn,Fe,Cd)SnS4 Thin Films.

High-quality Cu2(Zn,Fe,Cd)SnS4 (CZFCTS) thin films based on the parent CZTS were prepared by aerosol-assisted chemical vapor deposition (AACVD). Substitution of Zn by Fe and Cd significantly improved the electrical transport properties, and monophasic CZFCTS thin films exhibited a maximum power factor (PF) of ∼0.22 μW cm-1 K-2 at 575 K. The quality and performance of the CZFCTS thin films were further improved by postdeposition annealing. CZFCTS thin films annealed for 24 h showed a significantly enhanced maximum PF of ∼2.4 μW cm-1 K-2 at 575 K. This is higher than all reported values for single-phase quaternary sulfide (Cu2BSnS4, B = Mn, Fe, Co, Ni) thin films and even exceeds the PF for most polycrystalline bulk materials of these sulfides. Density functional theory (DFT) calculations were performed to understand the impact of Cd and Fe substitution on the electronic properties of CZTS. It was predicted that CZFCTS would have a smaller band gap than CZTS and a higher density of states (DoS) near the Fermi level. The thermal conductivity and thermoelectric figure of merit (zT) of the CZFCTS thin films have been evaluated, yielding an estimated maximum zT range of 0.18-0.69 at 550 K. The simple processing route and improved thermoelectric performance make CZFCTS thin films extremely promising for thermoelectric energy generation.

Symmetry-induced modulation of proton conductivity in Y-doped Ba(Zr,Ce)O3: insights from Raman spectroscopy

Quantitative comparison of crystal symmetry and lattice volume effects on the proton conductivity of Y-doped Ba(Zr,Ce)O3 epitaxial films to polycrystalline bulk materials reveals that lower crystal symmetry correlates with higher activation energy.

Solvothermally silver doping boosting the thermoelectric performance of polycrystalline Bi2Te3

Bismuth telluride (Bi2Te3) is one of the most promising thermoelectric materials for commercial application at room temperature, but the thermoelectric performance of these materials still needs to be improved. In this study, we report a type of solvothermally Ag-doped Bi2Te3 microplate. By sintering these microplates into polycrystalline bulk materials, a high room-temperature figure of merit of 1 has been achieved. Based on comprehensive micro/nanostructural characterizations, we found that the solvothermally doped Ag in Bi2Te3 plays two main roles, namely as the dopants that effectively induce the point defects of AgBi and forming Ag2Te nanophases. AgBi can provide additional hole charge carriers, effectively adjusting the initially high electron carrier concentration in the system, while the Ag2Te nanophases effectively trigger energy filtering effect to maintain a high Seebeck coefficient, thereby contributing to a competitively high power factor of 25.5 μW cm−1 K−2 at 298 K. Simultaneously, a low thermal conductivity of 0.74 W m−1 K−1 is obtained due to the strong phonon scattering at various lattice imperfections, induced by the solvothermally Ag-doping, which include point defects, grain/phase boundaries, local lattice distortions, and dislocations. This work fills the gap in knowledge on the solvothermally Ag-doping mechanism in Bi2Te3 and provides guidance for the innovative design of high-performing inorganic thermoelectrics.

In-plane lattice thermal conductivity predictions of thin films within columnar grains

Polycrystalline thin films are widely used for devices and energy-related applications, such as power electronics, solar cells, and thermal management of devices. In many cases, large-scale crystallization during thin-film growth is challenging, so columnar grains are often found in metal and semiconductor thin films. These rough columnar grain boundaries may also have different phonon specularities from that for typically smoother top/bottom film surfaces. A simple analytical model to separately treat these boundaries and interfaces for phonon scattering is currently unavailable, although the in-plane thermal transport is critical to heat spreading within thin-film devices. In this paper, we extend the effective medium formulation from three-dimensional polycrystalline bulk materials to columnar-grained thin films. The model predictions agree well with those given by frequency-dependent phonon Monte Carlo simulations, considering varied phonon specularity at top/bottom film surfaces and grain-boundary phonon transmissivity. The analytical model is further used to analyze the existing data on polycrystalline ZnO thin films with columnar grains.

Controllable 2H/3R phase transition and conduction behavior change in MoSe2:Nb substitution by high pressure synthesis for promising thermoelectric conversion

Transition metal dichalcogenides (TMDs) are uniquely multifunctional materials with optical, electronic, and catalytic properties. Despite the advantages of low cost, low toxicity, and high abundance, the thermoelectric transport properties of MoSe2 were not extensively investigated. Meanwhile, MoSe2 bulk material with 3R phase was rarely reported compared to 2H phase. In this work, controllable phase transition from 2H to 3 R for MoSe2 bulk polycrystalline material was achieved with various Nb contents by a simple and feasible high-pressure method. The preferred orientation resulted in anisotropy of both electrical and thermal transport. The samples converted from n type for pristine sample to p type conduction after Nb doping. Meanwhile, the conduction type gradually changed from semiconductor to degenerated semiconductor. The electrical properties were distinctly improved by Nb doping systematically from the reduced bandgap and the enhanced carrier concentration and mobility. The lattice thermal conductivity was reduced by point defects and grain/phase boundaries generating from Nb doping. Maximum zT of 0.17 at 873 K was obtained for Nb0.04Mo0.96Se2, which is among the highest values for Te-free Mo dichalcogenides. The strategy of chemical doping and high-pressure synthesis provides an alternative route to achieve MoSe2 bulk materials with a controllable 2H/3R phase ratio for potential applications, which can be extended to other TMDs.

Local Three-Dimensional Characterization of Nonlinear Grain Boundary Length within Bulk ZnO Using Nanorobot in SEM

Aiming at the problems of lack of data on the nonlinear morphology to divide uneven grain boundary in bulk ceramics, a unique approach of nanorobot-based characterization of three-dimensional nonlinear structure length can be creatively proposed under scanning electron microscope to quantify the actual morphology of local micro-area grain boundary in bulk ZnO. Contour shapes of the targeted grain boundaries in plane X-Y can be imaged using SEM. Z-directional relative height differences at different positions can be sequentially probed by nanorobot. Experiments demonstrate that it is effective to characterize three-dimensional length structures of nonlinear grain boundaries in bulk materials. By quantifying Z-directional relative height differences, it can be verified to show that irregular characteristics exist in three-dimensional grain boundary length, which can extend the depth effect on nonlinear bulk conductance. Furthermore, this method can also obtain nonlinear quantitative topographies to divide grain boundaries to uneven structure in the analysis of bulk polycrystalline materials.

Magnetic and Magnetocaloric Properties of Nano- and Polycrystalline Manganites La(0.7-x)EuxBa0.3MnO3.

Here, we report synthesis and investigations of bulk and nano-sized La(0.7-x)EuxBa0.3MnO3 (x ≤ 0.4) compounds. The study presents a comparison between the structural and magnetic properties of the nano- and polycrystalline manganites La(0.7-x)EuxBa0.3MnO3, which are potential magnetocaloric materials to be used in domestic magnetic refrigeration close to room temperature. The parent compound, La0.7Ba0.3MnO3, has Curie temperature TC = 340 K. The magnetocaloric effect is at its maximum around TC. To reduce this temperature below 300 K, we partially replaced the La ions with Eu ions. A solid-state reaction was used to prepare bulk polycrystalline materials, and a sol-gel method was used for the nanoparticles. X-ray diffraction was used for the structural characterization of the compounds. Transmission electron spectroscopy (TEM) evidenced nanoparticle sizes in the range of 40-80 nm. Iodometry and inductively coupled plasma optical emission spectrometry (ICP-OES) was used to investigate the oxygen content of the studied compounds. Critical exponents were calculated for all samples, with bulk samples being governed by tricritical mean field model and nanocrystalline samples governed by the 3D Heisenberg model. The bulk sample with x = 0.05 shows room temperature phase transition TC = 297 K, which decreases with increasing x for the other samples. All nano-sized compounds show lower TC values compared to the same bulk samples. The magnetocaloric effect in bulk samples revealed a greater magnetic entropy change in a relatively narrow temperature range, while nanoparticles show lower values, but in a temperature range several times larger. The relative cooling power for bulk and nano-sized samples exhibit approximately equal values for the same substitution level, and this fact can substantially contribute to applications in magnetic refrigeration near room temperature. By combining the magnetic properties of the nano- and polycrystalline manganites, better magnetocaloric materials can be obtained.

In-situ mapping characterization of structure and electrical property of grain boundary in polycrystalline ZnO using nanorobot in SEM

Different from the existing methods of individual characterization of structure or electrical property, a unique approach for in-situ mapping characterization of single grain boundary using nanorobot in SEM is proposed to simultaneously realize the characterization of structure and electrical property in micro-area polycrystalline ZnO. Z-direction height differences constructed by multiple adjacent grains relative to a single target grain can be individually probed by the nanorobot single end tip and correspondingly virtually reconstructed. Electrical impedances complex planes of grain boundaries in-situ detected by nanorobot dual probes can be fitted by equivalent circuits. Experimental results illustrate that in-situ mapping characterization of structure and electrical property of single grain boundary using nanorobot in SEM can be verified. A single grain boundary layer, composed of adjacent multi-grains, seems to be nonlinear and unequal height along the Z direction. Z-direction relative height differences probed by the nanorobot can actually be regarded as the Z-direction projected lengths of surrounding grain boundary interfaces of single target grain. A three dimensional stereogram of single target grain boundary can be virtually reconstructed based on 3D software. It is deduced that schottky barrier existing in grain boundary interface exhibits larger height difference, basically proportional to the thickness of grain boundary in plane X–Y. Furtherly, it can promote an advance in in-situ mapping characterization of structure-property of single/multi micro area in other bulk inorganic polycrystalline bulk materials.

Interface-Driven Multiferroicity in Cubic BaTiO3-SrTiO3 Nanocomposites.

Perovskite multiferroics have drawn significant attention in the development of next-generation multifunctional electronic devices. However, the majority of existing multiferroics exhibit ferroelectric and ferromagnetic orderings only at low temperatures. Although interface engineering in complex oxide thin films has triggered many exotic room-temperature functionalities, the desired coupling of charge, spin, orbital and lattice degrees of freedom often imposes stringent requirements on deposition conditions, layer thickness and crystal orientation, greatly hindering their cost-effective large-scale applications. Herein, we report an interface-driven multiferroicity in low-cost and environmentally friendly bulk polycrystalline material, namely cubic BaTiO3-SrTiO3 nanocomposites which were fabricated through a simple, high-throughput solid-state reaction route. Interface reconstruction in the nanocomposites can be readily controlled by the processing conditions. Coexistence of room-temperature ferromagnetism and ferroelectricity, accompanying a robust magnetoelectric coupling in the nanocomposites, was confirmed both experimentally and theoretically. Our study explores the 'hidden treasure at the interface' by creating a playground in bulk perovskite oxides, enabling a broad range of applications that are challenging with thin films, such as low-power-consumption large-volume memory and magneto-optic spatial light modulator.

Synthesis and Electronic Characterization of Weyl Semimetal TaSb2Polycrystalline Material

TaSb2, a candidate material for thermoelectric conversion, is studied to establish a method for the synthesis of polycrystalline bulk materials with a diameter greater than 10 mm. Polycrystalline TaSb2materials with relative densities exceeding 97% are successfully prepared by combining the solid‐state reaction method with the spark plasma‐sintering process. The prepared TaSb2sample is identified to be a semimetal with a pseudogap‐like electronic structure near the Fermi level using hard X‐ray photoelectron spectroscopy and band structure calculation.

Enhanced critical current density in K-doped Ba122 polycrystalline bulk superconductors via fast densification

SummaryIron-based superconductors are expected to be used in strong magnet applications owing to their excellent superconducting properties. The process of sintering a mechanically alloyed precursor powder is effective in achieving a high upper critical field and critical current density in BaFe2As2 (Ba122) polycrystalline bulk materials. However, when this process is applied to K-doped Ba122, which shows the highest critical temperature in the Ba122 family, suppressing the vaporization of potassium is challenging. In this study, spark plasma sintering (SPS) method was applied to K-doped Ba122 to achieve fast densification. In contrast to the conventional synthesis method, which requires several tens of hours, optimally K-doped bulks with near theoretical density were obtained after only 5 min of SPS, and the magnetic critical current density reached 105 A/cm2 at 5 K. The demonstrated superconducting properties suggest that this fast densification technique is a useful tool for applying K-doped Ba122 to bulk trapped field magnets.

Enhancement of the performance of planar perovskite solar cells by active-layer surface/interface modification with optimal mixed solvent-antisolvent post-treatment

Modification of perovskite films surface/interface through the solvent vapor post-treatment during the film annealing can significantly improve the morphology and crystallinity of the perovskite film, thus enhances the efficiency of the perovskite solar cells (PSCs). In this work, we used a solvent-antisolvent mixture of Dimethyl sulfoxide (DMSO) and chlorobenzene (CB) in the post-treatment of perovskite films during device fabrication to achieve a high-power conversion efficiency of 19.15% in planar perovskite solar cells. The use of chlorobenzene as an additive to DMSO in the post-treatment of the perovskite films was shown to optimize the its morphology and resulted in films with highly fused grains. The modified perovskite film surface not only showed a decreased number of pin-hole and trap density at the surface, but also an increase in the charge transfer at the interfaces and reduced the susceptibility to low-frequency interface polarization. Furthermore, the impedance spectroscopy and I–V characteristics of the electron-only PSC devices also verified the conclusions above. Overall, this work demonstrates mixed solvent-antisolvent post-treatments of perovskite films as an effective modification strategy to tune their surface/interface properties. This approach is anticipated to be extrapolated to other categories of polycrystalline bulk materials and devices. Applying an optimized Post-treatment to the perovskite films (in perovskite photovoltaics) through mixed solvent annealing - DMSO:CB 1:2 (v/v), modifies its’ bulk/interface properties to be more favorable for photovoltaic devices, leading to a 17.97% increase in power conversion efficiency in planar perovskite solar cells compared to control devices. • A new strategy for modifying the perovskite films surface/interface morphology and crystallinity to achieve the higher device performance through the mixed solvent-antisolvent (DMSO:CB) post treatment has been studied. • The addition of chlorobenzene in the treatment of the perovskite films has been found to achieve larger yet highly fused grains and a suppressed ionic contribution to the perovskite solar cell operation. • The stabilized power conversion efficiency of the planar perovskite solar cells with the optimized treatment has increased by 17.85%.

Formation of Dislocations and Stacking Faults in Embedded Individual Grains during In Situ Tensile Loading of an Austenitic Stainless Steel.

The formation of stacking faults and dislocations in individual austenite (fcc) grains embedded in a polycrystalline bulk Fe-18Cr-10.5Ni (wt.%) steel was investigated by non-destructive high-energy diffraction microscopy (HEDM) and line profile analysis. The broadening and position of intensity, diffracted from individual grains, were followed during in situ tensile loading up to 0.09 strain. Furthermore, the predominant deformation mechanism of the individual grains as a function of grain orientation was investigated, and the formation of stacking faults was quantified. Grains oriented with [100] along the tensile axis form dislocations at low strains, whilst at higher strains, the formation of stacking faults becomes the dominant deformation mechanism. In contrast, grains oriented with [111] along the tensile axis deform mainly through the formation and slip of dislocations at all strain states. However, the present study also reveals that grain orientation is not sufficient to predict the deformation characteristics of single grains in polycrystalline bulk materials. This is witnessed specifically within one grain oriented with [111] along the tensile axis that deforms through the generation of stacking faults. The reason for this behavior is due to other grain-specific parameters, such as size and local neighborhood.

Multiscale constitutive modeling of additively manufactured Al–Si–Mg alloys based on measured phase stresses and dislocation density

To better understand and predict the mechanical properties of additive manufacturing (AM) Al–Si–Mg alloys, developing a physically-based constitutive model is crucial. Among different models, the dislocation-density-based Kocks-Mecking (K-M) constitutive model has been widely used. Unfortunately, two challenges arise when the K-M model is used for the multiphase Al alloys. Firstly, an accurate K-M model demands the separation of phase stresses. Secondly, a thorough analysis of the K-M model involves the measurement of dislocation density during deformation. In-situ neutron diffraction, a powerful method to measure the phase stress and dislocation density in bulk polycrystalline materials under loading, is employed to investigate the AM AlSi3.5Mg1.5 and AlSi3.5Mg2.5 (wt.%) alloys. Based on the present results and reported data of AlSi10Mg, a multiscale constitutive model is developed for different AM Al–Si–Mg alloys. At the microscale, the evolution of dislocation density in the Al matrix with plastic strain can be well predicted by the K-M model. Meanwhile, the developments of the average stresses in different phases with plastic strain can be well captured by the Voce model. The measured microscopic k2/nc values agree with the theoretical value two of the K-M model quite well. Here, nc is the characteristic factor of the microscale Voce model, while k2 is the coefficient associated with the dynamic recovery process in the microscale K-M model. At the macroscale, the mechanical behavior can also be well reproduced by the K-M model and the Voce model. However, the macroscopic K2/Nc ratio is far away from two, where Nc and K2 are the characteristic factor and coefficient of the macroscale Voce model and K-M model, respectively.

Spectroscopic Ellipsometry for Simultaneous Thickness and Defect Concentration Changes in Oxide Thin Films

Measurements of strain and stoichiometry changes needed to determine coefficients of chemical expansion (CCEs) can be very time-intensive for bulk materials due to the long equilibration times needed at the multiple instruments and conditions. Additionally, bulk polycrystalline materials give macroscopic responses that include both lattice and microstructural contributions, and the responses are often therefore averaged over the randomized orientation of grains. Thin films provide an avenue to rapidly assess steady-state properties of such chemically expanding materials after short dwells due to their low volume and high surface area. Additionally, the controlled growth of thin films can be used to fabricate polycrystalline samples or single crystals with tailored crystallographic orientation, grain dimensions, and induced strain for controlled experiments. Although techniques exist for in situ analysis of thickness changes or defect concentration changes in thin films, there are few (if any) techniques that can measure both simultaneously. Further, the limited existing techniques to probe defect concentrations of thin films, e.g., in-plane electrical conductivity, cross-plane chemical capacitance, or in situ X-ray diffraction, require additional knowledge such as the dominant carrier mobility, the interface capacitance, or the coefficient of chemical expansion respectively (which is what we wish to determine).Spectroscopic ellipsometry has been widely used to analyze film thicknesses and optical properties, but we show that the optical properties obtained from the measurement can also be used to quantify defect concentrations, specifically oxygen non-stoichiometry. This work builds on our prior in situ optical absorption studies of oxygen concentrations and dynamics in thin films [1-4]. When we induce an oxygen stoichiometry change in a film, ellipsometry is, in principle, able to provide a measurement of the corresponding thickness change and oxygen stoichiometry change by a single technique.To evaluate the effectiveness of this technique initially, a SrTi0.65Fe0.35O3 thin film has been scanned after anneals in O2 and Ar. The modelled expansion and optical constants, derived from the data, were compared with previous work, and thicknesses were verified by X-ray reflectometry (XRR). For materials whose extinction coefficient corresponding to oxygen concentration is already known, the oxygen stoichiometry change can be estimated from the measured absorption coefficient change. Additionally, a variation of the Clausius-Mossotti equation is proposed to estimate the defect concentration in materials that lack prior optical extinction coefficient data corresponding to the defect of interest. These preliminary results suggest that spectroscopic ellipsometry may be used for the rapid acquisition of in situ data to quantify thin film CCEs in various environments.[1] Perry, N. H., Kim, J. J., & Tuller, H. L. (2018). Oxygen surface exchange kinetics measurement by simultaneous optical transmission relaxation and impedance spectroscopy: Sr (Ti, Fe) O3-x thin film case study. Science and Technology of advanced MaTerialS, 19(1), 130-141.[2] Perry, N. H., Pergolesi, D., Bishop, S. R., & Tuller, H. L. (2015). Defect chemistry and surface oxygen exchange kinetics of La-doped Sr (Ti, Fe) O3− α in oxygen-rich atmospheres. Solid State Ionics, 273, 18-24.[3] Chen, T., Harrington, G. F., Sasaki, K., & Perry, N. H. (2017). Impact of microstructure and crystallinity on surface exchange kinetics of strontium titanium iron oxide perovskite by in situ optical transmission relaxation approach. Journal of Materials Chemistry A, 5(44), 23006-23019.[4] Perry, N. H., Kim, N., Ertekin, E., & Tuller, H. L. (2019). Origins and Control of Optical Absorption in a Nondilute Oxide Solid Solution: Sr (Ti, Fe) O3–x Perovskite Case Study. Chemistry of Materials, 31(3), 1030-1041.