Crystallographic Characteristics Research Articles

Phyto-constructed copper urchin-like nanoflakes to facilitate the catalytic elimination of organic pollutants

In this context, Copper (Cu) nanoparticles were advanced the use of a sustainable technique for the synthesis addressing Morindacitrafolia leaf (MCL) extract. The fabricated of catalyst were technically examined by using TEM, XRD, SEM, EDAX, AFM, UV–Vis spectrophotometer, and FT-IR research were used to evaluate the topological, crystallographic, and structural features. The produced M@Cu Nano catalyst’s catalytic ability was examined for an interaction involving methyl orange dye under the presence of NaBH4 as an inhibiting agent. In an effort to achieve optimal reduced chemical conditions, the implications of the catalytic dosage, pH, and dye initial quantity was examined. The M@Cu Nano trigger, once developed, effectively eliminated 99.9 % of the harmful organic dyesof methyl orange, suggesting it may have utility towards the treatment of debris and polluted water. This investigation demonstrates the inexperienced synthesis of Cu Nanoparticles and its programs in environmental remediation.

Biosynthesis and characterizations of silver nanoparticles by using green banana peel extract: Evaluation of their antibacterial and electrical performances

Biosynthesized silver nanoparticles (Ag NPs) hold tremendous promise in nano-bioscience, with applications spanning engineering, science, and industry. This study delves into their fabrication process, crystallographic characteristics, and nanostructures. Employing green banana peel extract (GBPE), Ag NPs were synthesized. Various analytical techniques, such as UV–Vis absorption spectrophotometry (UV), X-ray diffraction (XRD), Gas chromatography-mass spectrometry (GC-MS), Field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), and Transmission electron microscopy (TEM) elucidate their attributes. UV–visible analysis reveals a 413 nm absorption band due to surface plasmon resonance. The Ag NPs exhibit a face-centered cubic structure with an average crystallite size of 45.87 nm. Lattice parameters and dislocation density are also determined. When tested against harmful bacteria, such as E. coli and S. epidermidis, advanced microscopy reveals a median size of particles of 55.12 nm and demonstrates their antibacterial characteristics. These environmentally benign Ag NPs also improve the efficiency of bio-electrochemical cells (BECs), opening the door to large-scale manufacturing at a reasonable cost and broadening the range of possible uses.

Hot corrosion behavior of multicomponent rare earth phosphate materials exposed to molten V2O5 salt

Six multi-component rare earth phosphate materials were prepared by chemical co-precipitation, which are (La0.2Nd0.2Sm0.2Eu0.2Gd0.2)PO4, (La0·2Ce0.2Nd0.2Sm0.2Eu0.2)PO4, (Ce0.2Nd0.2Sm0.2Eu0.2Gd0.2)PO4, (La0.5Nd0.5)PO4, (La0.5Gd0.5)PO4 and (Nd0.5Gd0.5)PO4. Hot corrosion behavior tests were conducted in molten V2O5 salt at 900 °C and 1000 °C for 20 h and 40 h, respectively. The results show that the corrosion temperature and the heat treatment time have little effect on the type of corrosion products. Among these materials prepared in this study, the material containing Gd element and the material without Gd element exhibit different hot corrosion behavior. For the multi-component rare earth phosphate materials containing Gd element, the corrosion product is ReVO4 (ReSm, Eu, Gd) xenotime, and a reaction layer is formed on the surface of the bulk. For the multi-component rare earth phosphate materials without Gd element, the corrosion product is Re(P,V)O4 (ReLa, Ce, Nd) solid solution and the amount of product is very small, the corrosion reaction is extremely weak and no reaction layer is formed. Although the molten salt mainly penetrates, the original structure of the bulk has not been damaged, which indicates that its hot corrosion resistance is good. The hot corrosion mechanisms of these six multi-component rare earth phosphates are studied based on the crystallographic characteristics of rare earth phosphates/vanadates.

Multimodal learning of heat capacity based on transformers and crystallography pretraining

Thermal properties of materials are essential to many applications of thermal electronic devices. Density functional theory (DFT) has shown capability in obtaining an accurate calculation. However, the expensive computational cost limits the application of the DFT method for high-throughput screening of materials. Recently, machine learning models, especially graph neural networks (GNNs), have demonstrated high accuracy in many material properties’ prediction, such as bandgap and formation energy, but fail to accurately predict heat capacity(CV) due to the limitation in capturing crystallographic features. In our study, we have implemented the material informatics transformer (MatInFormer) framework, which has been pretrained on lattice reconstruction tasks. This approach has shown proficiency in capturing essential crystallographic features. By concatenating these features with human-designed descriptors, we achieved a mean absolute error of 4.893 and 4.505 J/(mol K) in our predictions. Our findings underscore the efficacy of the MatInFormer framework in leveraging crystallography, augmented with additional information processing capabilities.

Synthesis of rGO/CoFe2O4 Composite and Its Magnetorheological Characteristics.

In this study, composite particles of rGO/CoFe2O4 were synthesized using a solvothermal method to fabricate a low-density magnetorheological (MR) material with enhanced sedimentation stability. The morphology and crystallographic features of rGO/CoFe2O4 were characterized via SEM, TEM, and XRD, and its magnetic properties were tested using VSM. The MR fluid was formulated by blending rGO/CoFe2O4 particles into silicone oil. Under different magnet strengths (H), a rotational rheometer was used to test its MR properties. Typical MR properties were observed, including shear stress, viscosity, storage/loss modulus, and dynamic yield stress (τdy) following the Herschel-Bulkley model reaching 200 Pa when H is 342 kA/m. Furthermore, the yield stress of the MR fluid follows a power law relation as H increases and the index changes from 2.0 (in the low H region) to 1.5 (in the high H region). Finally, its MR efficiency was calculated to be about 104% at H of 342 kA/m.

Green synthesis of chitosan- and fluoride-functionalized silver nanoparticles using Camellia sinensis: Characterization and dental applications

The development of new biocompatible and eco-friendly materials is essential for the future of dental practice, especially for the management of dental caries. In this study, a novel and simple method was applied for the green synthesis of silver nanoparticles (AgNPs) from the aqueous extract of Camellia sinensis (WT) and functionalized with chitosan (CHS) and NaF. The effects of WT_AgNPs application on demineralized dentin were evaluated for potential dental applications. The WT_AgNPs showed molecular groups related to organic compounds, potentially acting as reducing and capping agents. All AgNPs presented spherical shapes with crystal sizes of approximately 20 nm. Forty human molars were assigned to control: sound (SD) and demineralised dentine (DD), and experimental groups: WT_AgNPs, WT_AgNPs_NaF, and WT_AgNPs_CHS. Then, the NPs were applied to DD to evaluate the chemical, crystallographic, and microstructural characteristics of treated-dentine. In addition, a three-point bending test was employed to assess mechanical response. The application of WT_AgNPs indicated a higher mineralisation degree and crystallites sizes of hydroxyapatite than the DD group. SEM images showed that WT_AgNPs presented different degrees of aggregation and distribution patterns. The dentine flexural strength was significantly increased in all WT_AgNPs. The application of WT_AgNPs demonstrated remineralising and strengthening potential on demineralised dentine.

Nondestructive Single-Atom-Thick Crystallographic Scanner via Sticky-Note-Like van der Waals Assembling-Disassembling.

Crystallographic characteristics, including grain boundaries and crystallographic orientation of each grain, are crucial in defining the properties of two-dimensional materials (2DMs). To date, local microstructure analysis of 2DMs, which requires destructive and complex processes, is primarily used to identify unknown 2DM specimens, hindering the subsequent use of characterized samples. Here, a nondestructive large-area 2D crystallographic analytical method through sticky-note-like van der Waals (vdW) assembling-disassembling is presented. By the vdW assembling of veiled polycrystalline graphene (PCG) with a single-atom-thick single-crystalline graphene filter (SCG-filter), detailed crystallographic information of each grain in PCGs is visualized through a 2D Raman signal scan, which relies on the interlayer twist angle. The scanned PCGs are seamlessly separated from the SCG-filter using vdW disassembling, preserving their original condition. The remaining SCG-filter is then reused for additional crystallographic scans of other PCGs. It is believed that the methods can pave the way for advances in the crystallographic analysis of single-atom-thick materials, offering huge implications for the applications of 2DMs.

Room Temperature-Built Gas Sensors from Green Carbon Derivative: A Comparative Study between Pristine SnO2 and GO-SnO2 Nanocomposite

Room temperature-built gas sensors were fabricated from graphene oxide (GO), pristine and doped SnO2 nanostructures. The as-synthesized green carbon derivative (GO) nanomaterials were prepared from waste plastic precursor using Modified Hummer’s methodology. Pristine SnO2 and GO-SnO2 nanocomposite were synthesized employing a wet synthesis technique known as co-precipitation. The as-prepared nanoparticles were investigated for structural crystallographic and morphological features using X-ray diffractometry (XRD) and Transmission electron microscopy (TEM) analytical techniques. High-angle annular dark field (HAADF) and elemental quantifications of the nanopowders were investigated with the Energy dispersive X-ray spectroscopy (EDX). Textural features were determined with the assistance of Brunauer-Emmett-Teller (BET) analyzer. Thermogravimetric analysis (TGA) was performed to ascertain the material stability and degradability of the synthetic materials. Functional group and bond structure analysis was conducted using Fourier-transform infrared (FTIR) spectroscopy. Gas sensor devices were tested for responses towards CH4, H2, LPG, and CO2 gases at 20 ppm concentrations of each. GO-SnO2 nanocomposite sensing device showed optimal detection response towards the respective analyte gases with values of 5.00, 5.08, 4.90 and 3.41 respectively. The prepared nanocomposite showed stability and selectivity towards the target gases in an order of magnitude of H2 > CH4 > LPG > CO2. The optimal gas sensor device’s dynamic gas sensing response was ascribed to the GO doping effect which relatively increased its surface area (46.48 m2g-1) and absorption sites.

Improved Structural Description of Different γ-Al2O3 Materials Using Disordered δ5-Al2O3 Phase via X-ray Pair Distribution Function Analysis

Extensive research has been conducted in the past on the crystallographic characteristics of γ-Al2O3 support materials due to their advantageous properties in heterogeneous catalysis. While their structure is most commonly described as spinel, their intrinsic disorder and nanostructure have prompted alternative models involving tetragonal space groups, supercells, or occupancy of non-spinel positions. X-ray pair distribution function (PDF) analysis has further postulated the existence of short-range order domains with structural remnants from boehmite precursors from which γ-Al2O3 is commonly prepared via calcination. In this PDF study, we now show that a recently theoretically found monoclinic δ5-Al2O3 phase is, in fact, best suited for describing the structure of different commercial Al2O3 supports, as well as a self-prepared and an industrial Ni/Al2O3 methanation catalyst. Furthermore, in situ experiments under catalytic cycling in the methanation reaction demonstrate that the nanoscale structure of this δ5 phase is preserved during cycling, pointing towards the high stability of the therein-represented disorder. A complete description of the disordered Al2O3 support structure is crucial in the field of heterogeneous catalysis in order to distinguish disorder within the bulk support from additional interfacial restructuring processes such as surface oxidation or spinel formation due to nanoparticle–support interactions during catalytic cycling in in situ scattering experiments.

Supercapacitor Performance of MXene-Coated Carbon Nanofiber Electrodes

MXenes consisting of thin layers of transition metal carbides or nitrides are good candidates for electrode materials due to their excellent electrical conductivity and fast ion transfer. Electrospun carbon nanofibers are highly porous and electrically conductive, making them attractive for electrode materials. In this study, free-standing electrodes were prepared by the dip-coating of carbon nanofibers (CNFs) in the MXene (Ti3C2) colloidal solution, which was synthesized via the wet-etching of MAX (Ti3AlC2) phase, and their chemical structures were investigated by X-ray diffraction and Fourier transform infrared spectroscopy. In addition, scanning and transmission electron microscopy were used to investigate the morphological and crystallographic features of MXene-coated CNFs. Surface area and pore volumes were investigated by nitrogen adsorption/desorption measurements. Supercapacitor performance was studied by assembling a 3-electrode system with 1M aqueous sodium sulfate solution as an electrolyte. MXene-coated CNFs exhibited a maximum specific capacitance of 514 F/g at 0.5 A/g, with energy and power densities of 71.4 Wh/kg at 0.5 A/g and 2.3 kW/kg at 5 A/g, respectively, which are relevantly higher compared to the pristine CNFs due to the pseudocapacitive behavior of MXenes. They also showed comparable cyclic stability during 5000 cycles with the CNFs. This result indicates that MXene-coated carbon nanofibers can be effective electrode materials for electrochemical energy storage.

Effects of acicular ferrites on crystallography and incomplete transformation of low-carbon low-alloy steel

In this study, we investigated the effects of acicular ferrite (AF) on the crystallographic and incomplete transformation characteristics of low-carbon low-alloy steel. Intermediate annealing after austenitization induced a transformation yielding AFs, accelerating the isothermal transformation kinetics and regulating the microstructure. This process formed highly dense packet grain boundaries and improved the stability of untransformed austenite. AF formation increased the number of packet interfaces, increasing the crack propagation energy. The reduction and refinement of martensite/austenite (M/A) islands increased the crack nucleation energy. A displacive model was used to fit the transformation kinetics curve, indicating the significant effect of the nucleation rate on the isothermal transformation of the experimental steel at 450, 475, and 500 °C. The findings of this study indicate that nucleation regulation can accelerate transformation kinetics to strengthen and toughen bainitic structures.

Acicular Ferrite Identification in Heat‐Affected Zone of a Ti‐Killed High Strength Low Alloy Steel

It is frequently found in the literature that an acicular ferrite (AF) dominant microstructure has unsteady or even low‐impact toughness. It is necessary to analyze whether they are qualified for real AF. Herein, a Ti‐killed high strength low alloy steel is prepared and subjected to heat‐affected zones simulation tests to induce various AF‐like microstructures. The morphological differences of these microstructures are compared, and their crystallographic characteristics are analyzed. It is found that even within a single prior austenite grain, the transformed microstructure can be heterogeneous. Local areas having clear lath boundaries and a chaotic or interlocking morphology should be classified as AF. Adjacent laths in these areas are from different close‐packed plane and Bain groups. In contrast, local areas having vague lath boundaries and a granular‐bainite‐like morphology should be classified as granular bainite. Neighboring laths in these areas are from the same Bain group, and a relatively low density of high‐angle grain boundaries can be found. The heterogeneous microstructure consisting of granular bainite and AF has a wider grain size distribution and a higher area fraction occupied by large grains, which can lead to the scatter of Charpy impact energy. Criteria for the identification of AF are also proposed in this research.

Origin and properties of kaolinites from soils of a toposequence in Southern Brazil

ABSTRACT Kaolinite is the main clay mineral in most soils around the world and has been widely used for industrial purposes. This research aimed to study chemical, morphological and crystallographic characteristics of kaolinite, and establish the origin of kaolinitic samples on Serra do Mar and kaolinitic layers on peatlands, located at Southern Brazil. Samples were collected on different geomorphological positions: two samples at Serra do Mar (kaolinitic saprolite – SAP, and kaolinitic layers - KL); and two cores at the peatland with Sapric Histosols from Quaternary sedimentary basin. Granulometry and total organic carbon (TOC) were determined in soil samples. Kaolinite in silt and clay fractions was studied by chemical extractions, X-ray diffraction (XRD), thermal analysis (DTA/TG), and scanning electron microscopy with energy dispersive spectroscopy – SEM/EDS. Chemical and mineralogical characteristics of kaolinite were divided into two groups, according to the particle size and the location of the deposit in the relief. Silt fraction: i) SAP – genesis mainly derived from mica weathering; ii) peatland, containing pseudomorph crystals smaller than those found in Serra do Mar; Clay fraction: i) Serra do Mar – there was a larger contribution of K-feldspar weathering in the genesis of kaolinite from KL in relation to SAP; ii) peatland – the stronger weathering and the hydromorphic conditions resulted in less neoformed crystalline kaolinites. For both environments, the substitution of Al 3+ by Fe 3+ into the octahedral sheet led to a reduction in the mineral thickness and also increased the occurrence of structural deformations in clay kaolinite. Kaolinite in peatland is a combination of the following genesis processes: transportation from Serra do Mar (mainly in the silt fraction) and; formation in situ through neogenesis process (dominant in the clay fraction).

Revisiting the Crystallography of {225}γ Martensite: How EBSD Can Help to Solve Long-Standing Controversy

Explaining the crystallography of iron alloys martensite with a {225}γ habit plane remains a challenging task within the phenomenological theory of martensite crystallography. The purpose of this study is to re-examine the martensite formed in a Fe-8Cr-1.1C alloy using EBSD, which has a better angular resolution than the conventional transmission electron diffraction techniques previously used. The results show that the single morphological plates, which hold a near {225}γ habit plane, are bivariant composites made up of two twin-related variants. It is shown that a {113}γ plane is systematically parallel to one of the three common 112α planes between the two twin-related crystals. This observation suggests that the lattice invariant strain of transformation occurs through a dislocation glide on the {113}γ ⟨110⟩γ system, rather than through twinning as is commonly accepted. Based on this assumption, the predictions of Bowles and Mackenzie’s original theory are in good agreement with the crystallographic features of {225}γ martensite. Unexpectedly, it is the high shear solution of the theory that gives the most accurate experimental predictions.

Effects of Nd:YAG laser irradiation at different energy densities on dentin bond durability under simulated pulpal pressure.

To evaluate the effects of Nd:YAG laser irradiation on the microstructures of dentin surfaces and the long-term bond strength of dentin under simulated pulpal pressure. Under simulated pulp pressure, 30 freshly extracted caries-free third molars were cut into 2-mm-thick dentin samples and then divided into five groups: the control and laser groups (93.3J/cm2; 124.4J/cm2; 155.5J/cm2; 186.6J/cm2). Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and Vickers hardness were used to analyze the surface morphology, composition, and mechanical properties of the dentin before and after laser irradiation. Another 80 caries-free third molars were removed and treated as described above, and the resin was bonded to the dentin surface with Single Bond Universal (SBU) adhesive in self-etch mode to make stick specimens. Microtensile bond strength (µTBS), confocal laser scanning microscopy (CLSM), and interfacial silver nanoleakage tests before and after 10,000 times thermocycling were then performed to analyze the bonding properties and interfacial durability of each group. SEM observations revealed that the surfaces of all laser group specimens were rough with open dentin tubules. Laser irradiation altered the surface composition of dentin while removing some collagen fibers but did not affect its surface hardness or crystallographic characteristics. Furthermore, laser irradiation with an energy density of 124.4J/cm2 significantly promoted the immediate and aging bond strengths and reduced nanoleakage compared to those of the control group. Under simulated pulp pressure, Nd:YAG laser pretreatment altered the chemical composition of dentin and improved the immediate and long-term bond strength. This study investigated the optimal parameters for Nd:YAG laser pretreatment of dentin, which has potential as a clinical method to strengthen bonding.

Crystallographic and Topographic Analysis of Ultra-Translucent Zirconia After Various Surface Treatments

The aim of the present study was to analyze the effects of 4 different surface treatments, on the crystallographic characteristics of Ultra-Translucent Zirconia. Fully sintered zirconia specimens of highly translucent yttria partially stabilized zirconia (Y-PSZ) (KATANA UTML) were divided into four experimental groups and a control group (n=10). Each group received one of the following surface treatments: sandblasting with 50µm alumina particles (Al₂O₃), sandblasting with 110µm alumina particles, and grinding with a rotary high-speed turbine with and without water irrigation. For each sample, x-ray diffraction was carried out to analyze peak intensity, calculate the crystallite size, and detect the presence of compressive and tensile stress. Surface roughness was measured on all specimens using a standard scanning profilometer. Additionally, scanning electron microscopy (SEM) was performed to qualitatively analyze the surfaces of the specimens. Statistical analysis included repeated measures analysis of variance and post hoc Tukey test (p≤0.05). The control group exhibited the highest crystallite size (323nm). All surface treatments led to a reduction in the crystallite size, with the most significant reduction observed in the groups subjected to sandblasting with 110µm alumina particles and high-speed grinding with irrigation. Sandblasting with 50µm alumina particles resulted in less transformation of the crystallite size. A general tendency of the diffraction peaks to shift to a lower angle can be observed in the experimental groups, indicating the presence of compressive stress on the samples. Profilometry revealed higher roughness in the ground samples (6,14µm and 6,57µm) compared to the sandblasted groups (2,93µm and 2,02µm). The crystal domain size showed a tendency to decrease after the surface treatments. Sandblasted samples, as well as ground samples without irrigation, exhibited compressive stress. Sandblasted samples had lower surface roughness compared to the ground samples. Sandblasting with 50µm alumina particles caused the least decrease in crystallite size.

A novel low loss rare-earth germanate La4GeO8 microwave dielectric ceramic with orthorhombic structure

This study delves into the synthesis and characterization of rare earth germanate La4GeO8 ceramics, employing the solid-phase reaction method, with a focus on their microwave dielectric properties and crystallographic characteristics. The research employs X-ray diffraction (XRD) and transmission electron microscopy (TEM) to ascertain the orthorhombic crystal structure within the Pnma space group. Rietveld refinement analysis precisely determines the lattice constants (a = 18.3006 Å, b = 7.6697 Å, c = 5.8513 Å) and unit cell volume (V = 821.28429 Å3). Raman spectroscopy provides insights into the correlation between the quality factor (Q × f) and the Full Width at Half Maximum (FWHM) of the Ag(O) mode at 733 cm⁻1. A notable highlight of the study is the exceptional microwave dielectric performance of La4GeO8 ceramic sintered at 1540 °C, characterized by a relative dielectric constant (εr) of 13.24, a Q × f product of 47,826 GHz at 10.16 GHz, and a temperature coefficient of frequency (τf) of −82.3 ppm/°C. This comprehensive investigation offers valuable insights into the structural and microwave dielectric properties of AB-type rare earth germanate La4GeO8 ceramics, underscoring their potential in advanced dielectric material applications.

Translating microcalcification biomarker information into the laboratory: A preliminary assessment utilizing core biopsies obtained from sites of mammographic calcification

Rationale and objectivesThe potential of breast microcalcification chemistry to provide clinically valuable intelligence is being increasingly studied. However, acquisition of crystallographic details has, to date, been limited to high brightness, synchrotron radiation sources. This study, for the first time, evaluates a laboratory-based system that interrogates histological sections containing microcalcifications. The principal objective was to determine the measurement precision of the laboratory system and assess whether this was sufficient to provide potentially clinical valuable information. Materials and methodsSections from 5 histological specimens from breast core biopsies obtained to evaluate mammographic calcification were examined using a synchrotron source and a laboratory-based instrument. The samples were chosen to represent a significant proportion of the known breast tissue, mineralogical landscape. Data were subsequently analysed using conventional methods and microcalcification characteristics such as crystallographic phase, chemical deviation from ideal stoichiometry and microstructure were determined. ResultsThe crystallographic phase of each microcalcification (e.g., hydroxyapatite, whitlockite) was easily determined from the laboratory derived data even when a mixed phase was apparent. Lattice parameter values from the laboratory experiments agreed well with the corresponding synchrotron values and, critically, were determined to precisions that were significantly greater than required for potential clinical exploitation. ConclusionIt has been shown that crystallographic characteristics of microcalcifications can be determined in the laboratory with sufficient precision to have potential clinical value. The work will thus enable exploitation acceleration of these latent microcalcification features as current dependence upon access to limited synchrotron resources is minimized.

Microstructural Evolution in a 0.09% Niobium Low Carbon Steel during Controlled Hot Deformation

A series of plane strain compression tests were carried out in order to simulate the thermomechanical controlled processing of a 0.09wt% Nb low carbon steel, in a scheme of multipass finish rolling at 950 °C with interpass times of 10 s. It was observed that after the first two finishing passes a remarkable grain refinement can be achieved, since the recrystallisation was fully suppressed and abundant ultrafine ferrite was transformed dynamically during the deformation. The addition of a third finishing pass however, led to partial recrystallisation. A deep characterisation of the dynamic ferrite was carried out by diverse methods conducting to relevant findings that contribute to a better elucidation of the dynamic transformation. The results obtained indicated that the dynamic formation of a colony of Widmanstätten ferrite plates during deformation, initiates with the formation of a pair of self-accommodating plates followed by face-to-face sympathetic nucleation of new plates at one of the faces of the pairs of plates already formed. Furthermore, the crystal orientation within the dynamic ferrite phase was analysed with EBSD, it was observed that during the coalescence of plates, prior to the full polygonisation of grains, the ferrite adopts a transitory morphology which possesses particular crystallographic characteristics.

Effect of Ge Incorporation on Lead‐free Cs‐based Triiodide Sn−Ge Co‐alloy Perovskite Thin Films by Spin Coating

AbstractA new Sn−Ge co‐alloy perovskite that does not contain toxic Pb is attracting attention due to its excellent predicted optoelectronic properties. However, most current research only focuses on compositions with Ge content up to 50 %, resulting in a limited overall understanding on this material system. In this study, CsSn1–xGexI3 (0≤x≤1) perovskite thin films were fabricated using spin coating method and characterized in terms of crystallographic, morphological and optical characteristics systematically. The results show that the Ge incorporation causes lattice shrinkage and a change in the crystallographic phase from orthorhombic to trigonal. Additionally, the coverage varies much as Ge increases. The Ge incorporation also results in a blueshift of the photoluminescence peak and a decrease in luminescence intensity as compared to the composition with lower Ge content. Moreover, the carrier dynamics measurement shows that the Ge incorporation increases the carrier nonradiative recombination. This work provides important hints for the development of the Sn−Ge alloy‐based perovskite solar cell.