Solution Growth Research Articles

Spatial bandgap tailoring via a novel injection chemical bath deposition enables highly efficient carbon-based Sb2(S,Se)3 thin film solar cells

In recent years, significant progress has been made in the fabrication of sulfoselenide Sb2(S,Se)3 solar cells using a widely adopted hydrothermal method. However, the record efficiency is still far behind the theoretical values partly due to an unfavorable spatial bandgap distribution, which is induced by the complicated chalcogenide growth kinetics of the hydrothermal synthesis. Herein, a novel solution growth method, called Injection Chemical Bath Deposition (ICBD), is developed to prepare Sb2(S,Se)3 alloys for the first time. With this open CBD process, the selenium (Se) source is facilely incorporated during intermediate stages of reaction, and then successfully constructing a V-shaped bandgap via carefully tailoring the vertical gradients in chemical constituents, which synergistically enhances light absorption and carrier separation in the Sb2(S,Se)3 absorber. As a result, the solar cell with a full-inorganic FTO/CdS/Sb2(S,Se)3/Carbon structure achieves an impressive conversion efficiency of 7.63 %, which is among the highest efficiency of carbon-based Sb2(S,Se)3 solar cells based on CBD method. This study demonstrates a flexible strategy for manipulating the gradient band gap for highly efficient Sb2(S,Se)3 solar cells.

Growth, structural, optical, thermal and terahertz time-domain spectroscopy of l-alanine single crystal: A potential amino acid based nonlinear optical material

In our present work, we focused on the terahertz (THz) based characterization of a very efficient organic nonlinear optical (NLO) single crystal of l-alanine (LA). Using the well-known slow evaporation solution growth method (SEST), an optically transparent amino acid-based LA crystal was effectively grown at room temperature. The structural information of the titled crystal was analyzed using powder X-ray diffraction (PXRD) which confirms the space group P212121 and orthorhombic structure of the crystal. Chemical etching of an as-grown single crystal was analyzed to identify the growth patterns. Fourier transform infrared (FTIR) and FT-Raman spectrometry were used to figure out the major functional groups that were present in the ingot crystal. The optical behaviour of LA crystal was observed through UV–Vis and Photoluminescence (PL) spectroscopies. The single crystal was found to have high transmission values over a wide range of wavelength. The PL results revealed that the main emission happens at 474 nm. Thermal stability of the titled compound was acquired by thermo-gravimetric and the differential thermo-gravimetric (TG-DTG) analysis. Open and closed aperture Z-scan measurements were used to analyze the third order nonlinear behavior of the as-grown sample using a femtosecond Ti-sapphire laser. To analyze the absorption peaks behavior Terahertz time-domain spectroscopy (THz-TDS) was also performed in the range 0.2–2.0 THz. The above study shows variation in absorption coefficient and refractive index at THz frequencies.

Sigma phase precipitation and growth in solution annealed 321 stainless steel during thermal aging: Effects on toughness & intergranular corrosion

Sigma (σ) phase is considered as one of the most deleterious phases in stainless steels (SS) due to its detrimental effects on mechanical and corrosion properties. In this work, σ phase formation and growth in annealed SS 321 (without δ-ferrite) and its effects on impact toughness and intergranular corrosion (IGC) were investigated, following thermal aging at 750 °C up to 5500 h. Microstructural characterization using X-ray diffraction and electron microscopy techniques revealed (a) precipitation of intergranular Cr-rich M23C6 and fine Ti-rich intra & intergranular carbides after short aging time of 27 h, (b) σ phase nucleation at the Cr-rich M23C6 - austenite interfaces after 100 h of aging and (c) σ phase at the austenite grain boundaries (GBs) beyond 700 h of aging. The experimental results, combined with thermodynamic calculations (ThermoCalc) showed that the meta stable Cr-rich carbide is the source of σ phase nucleation. σ phase started to grow at the expense of Cr-rich M23C6, and further, its size increased preferentially along the GB and into one of the austenite grains with increase of aging duration. Hardness remained in the range of 190–200 HV for all the specimens aged beyond 100 h and is shown to be due to stable Ti-rich intragranular carbides of 7–20 nm size. Impact toughness values decreased with the growth of σ phase, and up to 50% reduction in toughness was found by about 1% σ phase, with a ductile-brittle cleavage fracture. The normalized values of σ phase fraction, determined from its size and the toughness values, with aging duration followed Kolmogorov-Johnson-Mehl-Avrami (KJMA) model and both yielded the same empirical rate constant (k) of 2.7 × 10−7/s and the n value of ∼1. The lower k value and the n value of 1 suggest slower kinetics and one-dimensional growth of σ phase, which is in well agreement with microstructural observations. Susceptibility to IGC was seen in specimens with sub-microscopic σ phase (aged up to 100 h). However, aging beyond 700 h decreased resistance to uniform corrosion due to σ phase growth.

Preparation and characterization of molybdenum trioxide/poly(3,4-ethylenedioxythiophene): Polystyrene sulphonate nanocomposites for electrochromic application.

Electrochromic processes are mostly characterized by colour change arising from the energy of a chemical reaction involving electron transfer. Transition metal oxides of tungsten, molybdenum, iridium, and nickel show the most intense Electrochromic colour changes and photochemical stability of about 100 cycles compared to organic electrochromes which are susceptible to photochemical degradation. The prospect of conjugated polymers (comprising of metal oxides and polymers) has opened a new dimension on improving the Electrochromic performance of the transition metal oxides. In this work, solution growth methods were employed in preparing a MoO3/PEDOT: PSS composite layer by adding PEDOT: PSS into MoO3 aqueous dispersion resulting in an electrostatic interaction between MoO3 and PEDOT: PSS for electrochromic application. This composite has shown a long-term stability up to more than 550 cycles which shows higher potential specific capacitance than WO3/PEDOT: PSS. This approach has significantly improved the stability issue of MoO3 and enhances the potential of MoO3-based materials for electrochromic applications. The semi crystalline nature of MoO3-300 °C was further proved by FE-SEM observation of the MoO3 nanoparticles. The particle size shown in the images corresponds with FE-SEM result and polycrystalline structure was observed under high magnification. The polycrystalline nature of the MoO3 particles favors their electrochemical stability, while their small size facilitates their effective interactions with PEDOT: PSS. The electrochemical properties of MoO3, PEDOT: PSS and composite were further studied by cyclic voltammetry (CV) from -1 V to +1 V. MoO3 has a broad oxidation peak at -0.43 V and no obvious reduction peak in this range. PEDOT: PSS has an oxidation peak at -0.02 V and a reduction peak at -0.55 V. In the composite, the peak at -0.43 V becomes a shoulder and a new pair of redox peaks appear at -0.18 V/-0.09 V.

Synthesis, Crystal Structure, Spectroscopic Characterization and Anti-COVID-19 Molecular Docking Investigation of 2-(2-Formylphenoxy)acetamide

Compound 2-(2-formylphenoxy)acetamide was synthesized by adopting the slow evaporation solution growth technique. The spectroscopic techniques were studied experimentally and theoretically at DFT for the title compound. The X-ray diffraction analysis confirmed its crystal structure. The compound with the molecular formula C9H9NO3 crystallizes in the monoclinic crystal system with the centrosymmetric space group P21/n. The optimized structure, stability, hardness, softness, Mulliken charge distribution and molecular electrostatic potential (MEP) of the grown crystal were investigated using DFT calculations. Molecular docking studies were performed for the compound to evaluate its antiviral activity against SARS-CoV-2. The molecule has good binding affinity for the target protein 6NUS.

Development of continuous solution growth method for growth of large and high-quality perovskite single crystals

Large perovskite single crystals with high quality cannot be obtained by traditional batch-type solution growth techniques, impeding their use in commercial applications. We report on developing a continuous solution growth (CSG) method that enables the growth of large, high-quality perovskite single crystals such as methylammonium lead tribromide (MAPbBr3), as well as triple-cation mixed hybrid. A 40 × 40 × 2 mm3 MAPbBr3 single crystal grown by this method, has a high mobility-lifetime (µτ) product of 3.3 × 10−3 cm2·V−1 and a low trap density of 8.22 ± 0.02 × 108 cm−3. Photoconductors (Au-MAPbBr3-Au) with a low dark current density of 3.9nA·cm−2 at 0.83 V·mm−1 exhibit excellent photons detection of both UV–visible and X-ray photons. For UV–visible photons, the responsivity is about 1.5 A·W−1 and 1.3 A·W−1 to 405 nm and 532 nm photons, respectively; for X-ray sensitivity is up to 2.35 × 105 µC Gyair−1 cm−2 and the lowest detection limit is 15.7 nGyair·s−1. High-contrast X-ray images were obtained with a large (40 mm × 40 mm) pixelated detector with 800 µm × 800 µm pixels. These results demonstrate that the CSG technique can produce high-quality, large perovskite single crystals for commercial applications, including photodetection and ionization radiation detection.

Effect of Ca2+ ions on structure and spectroscopic properties of Er3+: KBaY(MoO4)3 crystals

This study successfully grew KBaY(MoO4)3 crystals doped with single Er3+ ions and co-doped with Ca2+/Er3+ ions using the top-seeded solution growth method. Thermal analysis of the KBaY(MoO4)3 crystals was performed by differential scanning calorimetry, and their phase and structure were characterized using X-ray diffraction and Fourier transform infrared spectroscopy. The luminescent properties of the crystals in the visible and near-infrared wavelength ranges under different concentrations of Er3+ ions were analyzed through emission spectroscopy, and the concentration quenching mechanism was investigated in depth. The results showed that the strongest emission intensity was obtained at an Er3+ ion concentration of 5 mol%. Additionally, by substituting Ba2+ ions with Ca2+ ions, the emission intensity was significantly enhanced, especially when the Ca2+ ion doping concentration reached 6 mol%, resulting in the maximum emission intensity. Furthermore, we investigated the effects of matrix structure and lattice distortion on the spectral properties by employing Judd-Ofelt (J-O) theory and studying energy transfer mechanisms. The mechanisms of Ca2+-induced fluorescence quenching and factors influencing the fluorescence decay time were analyzed. Through the analysis of the absorption cross-section, emission cross-section, and gain cross-section of crystals with different Ca2+ ion concentrations, it was found that Ca2+, Er3+: KBYM crystals exhibited a low laser pump threshold. The results demonstrate that the 6 mol% Ca2+, 5 mol% Er3+: KBYM crystals possess excellent performance and are a promising laser gain medium.

Crystal growth and characterization of piperazinium mercuric chloride (PMC) single crystal for nonlinear optical (NLO) application

A single organic NLO crystal of piperazinium mercuric chloride (abbreviated as PMC) was grown from water solvent by the conventional solution growth method. The synthesised PMC crystal was purified by repetitive recrystallization. The PMC structure was confirmed by single-crystal X-ray diffraction analysis. Various other characterizations were carried out for the grown PMC single crystal, such as Powder X-ray diffraction analysis, UV–Visible-NIR, High resolution X-ray diffraction, Fourier Transform Infrared analysis, Nuclear magnetic resonance, Photoluminescence, Photoconductivity, Chemical etching, Dielectric analysis, Vickers microhardness, and Third harmonic generation (Z-Scan) analysis. The above-mentioned analyses revealed the various planes (h, k, and l) of crystal structure, optical analysis, crystalline perfection, structural analysis, etch pit density, mechanical stability, electrical analysis, and NLO properties of the grown crystal.

Microstructure and Mechanical Properties of AA 6082/AISI 304 Joints Brazed Using Al-Ge-Si Filler Metal

Joining aluminum alloys with stainless steel is of great importance in many industrial sectors. Due to the low solidus temperatures of high-strength aluminum alloys, brazing with commercially available filler metals is not possible. Al-Ge-Si filler metals with a lower melting temperature of about 490 °C allow these alloys to be joined. They are manufactured in the form of foil via ultrafast solidification. AA 6082/AISI 304 joints are produced via induction brazing and vacuum furnace brazing. In this study, the tensile shear strength and the fatigue behavior of joints are investigated. Joints produced via induction brazing reached a maximum joining strength of 53 MPa, while vacuum-brazed joints achieved a maximum of 20 MPa. The fracture occurs in the reaction zone, especially inside the Al7Fe2(Si,Cr) intermetallic layer. The results of the fatigue tests show that the joints produced via induction brazing achieved 1 × 107 cycles at a stress amplitude of 7 MPa. Vacuum-brazed joints reached this at a stress amplitude of 3 MPa. All fatigue-tested samples fail in the reaction zone. The high hardness and growth of the SiGe solid solution and the Al7Fe2(Si,Cr) intermetallic layer had a major influence on the joining strength and fatigue behavior of AA 6082/AISI 304-brazed joints.

Physicochemical and Nonlinear Optical Properties of a Stilbazolium Family Single Crystal with Third Order Nonlinear Optical Activity

AbstractA novel counter anion group was incorporated with the organic stilbazolium cation (C16H19N2+) to yield a new third‐harmonic‐generation‐active single crystal of 4‐[2‐(4‐dimethylamino‐phenyl)‐vinyl]‐1‐methyl‐pyridinium 2‐nitroaniline‐4‐sulfonate (DSNA). The slow evaporation solution growth technique is employed to obtain DSNA crystals, whose nonlinear responses are analysed through a continuous wave laser Z scan experiment. The thermally induced strong reverse saturation absorption and self‐defocusing behaviour of the DSNA crystal suggests that the material could be used as an optical limiting device. Optical characterization shows that the lower absorption edge falls in the visible region (530 nm), with a broad transparency range of 0.53 to 1 μm. Exploration of other optical constants, such as extinction coefficient (k=10−4), emission wavelength (602 nm – red light), optical (σopt=1010 Ωm−1) and electrical conductivity (σelc=1011 Ωm−1) also concludes that the DSNA crystal could be potentially employed in optoelectronic devices. The various bonds and their corresponding lengths and angles involved in the formation of DSNA ionic crystal are evaluated by means of single‐crystal X‐ray diffraction (SCXRD). Linear and nonlinear optical property findings undoubtedly affirm that the titular DSNA crystal is an effective nonlinear optical (NLO) crystal.

A methodical investigation on the growth and characterization of a third-order nonlinear optical novel co-crystal of 8-hydroxyquinolinium phthalate: X-ray, Hirshfeld surface, optical, mechanical, thermal and DFT analysis

A novel non-linear optical single crystal of 8-hydroxyquinolinium phthalate has been as-synthesised by a slow evaporation solution growth technique. Single-crystal X-ray diffraction analysis affirms that it belongs to a monoclinic crystal system. While UV–visible spectroscopy shows its optical transparency with a direct band gap of 2.80 eV, a photoluminescence study confirms a principal yellow emission at 370 nm excitation. Furthermore, the mechanical and thermal properties along with the functional groups’ study have also been laid out in this paper. Intermolecular interactions present in the crystal are ascertained from Hirshfeld surface and fingerprint plot studies. The Z-scan technique has reportedly affirmed third harmonics generation in the same. Theoretical calculations using DFT modelling further testify to the experimental observations thereby laying out the framework of the mentioned crystal in terms of its optimized geometry, molecular electrostatic potential, frontier molecular orbital, natural bond orbital and natural population analysis along with vibrational assignments and UV absorption analysis.

Blow up and Exponential Growth to a Kirchhoff-Type Viscoelastic Equation with Degenerate Damping Term

In this paper, we consider a Kirchhoff-type viscoelastic equation with degenerate damping term have initial and Dirichlet boundary conditions. We obtain the blow up and exponential growth of solutions with negative initial energy.

On the growth of solutions of complex linear differential equations with analytic coefficients in $\overline{\mathbb{C}}\backslash\{z_{0}\}$ of finite logarithmic order

In this article, we study the growth of solutions of homogeneous and non-homogeneous complex linear differential equations where the coefficients are analytic functions in the extended complex plane except a finite singular point with finite logarithmic order. We extend some previous results obtained very recently by Fettouch and Hamouda.

Study of the effect of consortia of PGPR on the growth of Trichosanthes cucumerina in a hydroponic system

Hydroponics is the method of growing plants using soil-less cultivation systems. Plant growth-promoting bacteria are the rhizosphere bacteria that help plant growth and suppress plant diseases. In this study, we have isolated PGPR from the hydroponic systems and tested the efficacy of a consortium on the growth of Trichosanthes cucumerina. Ten organisms were isolated from a pre-set hydroponic system, of which three were selected based on their plant growth-promoting abilities. The isolated strains were identified as Chryseobacterium jejuense, Pseudomonas oryzihabitans and Sphingomonas paucimobilis. These isolates produced high levels of indole-3-acetic acid as well as other plant growth-promoting factors such as cellulase, pectinase, and siderophore production. All three isolates showed biofilm formation and growth in nutrient solutions with high EC values, indicating their ability to adhere to plant root surfaces and survive in nutrient solutions to promote plant growth. A consortium of these organisms used in the deep-water hydroponic system of T. cucumerina showed a significant increase in the number of leaves and root mass compared to control plants. Since these PGPR isolates exhibited multiple traits beneficial to the host plant, it has opened new possibilities for commercial application of these isolates in the hydroponic systems.

Synthesis, experimental and theoretical studies of morpholinium bromide single crystal for NLO application

Due to the electronic applications, non-linear optical (NLO) materials are receiving research attention. A non-linear optical material, morpholinium bromide (MBr) single crystal with dimensions of 14 × 9 × 3 mm3 was grown successfully by slow evaporation solution growth technique. The synthesized crystal belongs to monoclinic crystal with space group P21/c, which was confirmed through single crystal XRD (SXRD) analysis. Further, powder XRD analysis was used to record several dispersion peaks and the presence of dispersion peak positions for the as-grown material is correlated with the scattering peak state. The optimised molecular structure, HOMO-LUMO, NBO, MEP and Mulliken atomic charges of MBr crystal were theoretically investigated using B3LYP with a 6–311 G ++(d, p) basis set. FTIR studies revelas the functional components present in the grown material. The optical band gap was found to be 3.3 eV with a transmittance cut-off wavelength of 362 nm. TG-DTA analysis was done to understand the as-grown MBr crystal's temperature withstanding capability by assessing the weight loss associated with the corresponding decomposition peak. The potential of the crystal to stand up to laser power is investigated using laser damage threshold (LDT) studies. The Z-scan study is implemented to the polished MBr crystal to assess its nonlinear refractive index (n2), absorption coefficient (β) and susceptibility χ(3) for its usefulness in optoelectronic applications.

0D Hybrid Cuprous Halide as an Efficient Light Emitter and X‐Ray Scintillator

AbstractDespite the extraordinary X‐ray scintillation performance of three‐dimensional (3D) lead perovskite nanocrystals (PNCs), the serious biotoxicity of Pb2+ and luminescent instability in water remain insurmountable obstacles for their applications in medical imaging. To address these drawbacks, herein, the study demonstrates one new lead‐free zero‐dimensional (0D) hybrid cuprous halide of single‐crystalline [BzTPP]2Cu2I4 (BzTPP = Benzyltriphenylphosphonium) as a satisfactory X‐ray scintillator. [BzTPP]2Cu2I4 displays broadband yellowish‐green light emission with a high photoluminescent quantum yield (PLQY) of 44.2% and large Stokes shift of 167 nm upon UV light excitation. High PLQY and negligible self‐absorption enable [BzTPP]2Cu2I4 to display impressive scintillation performance excited by X‐ray with a light yield of 27 706 photons MeV‐1 and low detection limit of 0.352 µGy s−1, surpassing typical 3D PNCs. More importantly, [BzTPP]2Cu2I4 represents extraordinary structural and luminescent stability in water for at least one month. The excellent and stable radioluminescence performance as well as solution growth method ensure a [BzTPP]2Cu2I4‐based screen for fine‐resolution X‐ray imaging with potential in radiography and inspection. This work highlights the multiple merits of low‐toxicity and cost, high light yield, and long‐term water‐stability of 0D hybrid cuprous halides as highly desirable X‐ray scintillators.

Data-Driven Reactivity Predictions between a Solute and Solvent for Inorganic Crystal Growth in Solution

Data-Driven Reactivity Predictions between a Solute and Solvent for Inorganic Crystal Growth in Solution

Rational Design of Benzo‐Crown Ether Electrolyte Additives for High‐Performance Li‐O2 Batteries

AbstractDespite theoretical predictions of exceptional gravimetric energy densities in Li‐O2 batteries (LOBs), the current research forefront faces challenges, including high charge overpotential, cathode clogging, parasitic reactions, and Li anode corrosion. Herein, benzo‐crown ethers (BCEs) with varying cavity sizes are used as electrolyte additives to exploit their strong binding toward Li+ and promote the solution growth of Li2O2 with reduced particle size. Notably, the cell with benzo‐18‐crown‐6 ether (B18C6) enables the largest discharge capacity of 14948 mAh g−1. Upon charging, these additives accelerate Li2O2 oxidation through the strong binding with Li+ and the extended electrolyte/Li2O2 interface, resulting in improved reversibility, reduced charge overpotential, and prolonged cycle life. Besides, these additives also stabilize the Li anode by regulating Li+ migration and electron exchange, reducing dendritic growth and anode corrosion. This work presents insights into the rational design of BCEs as additives for high‐performance LOBs.

Crystal Structure, Hirshfeld Surface, Optical, Thermal, NLO, and DFT Analyses of 5‐Methyl‐1H‐Imidazole‐3‐Ium‐4‐ Carboxybutanoate crystal

AbstractAn organic 5‐methyl‐1H‐imidazole‐3‐ium‐4‐carboxybutanoate (5MIC) co‐crystal is grown by slow evaporation solution growth technique (SEST) at room temperature. The 5MIC is synthesized using 4‐methylimidazole and glutaric acid in a 1:1 ratio using methanol as a solvent. The 5MIC crystal lattice parameters are identified using single‐crystal X‐ray diffraction analysis. The experimental X‐ray diffraction (XRD) and DFT structural parameter values have good correlations. The intermolecular interactions of the 5MIC crystal are found using Hirshfeld surface and 2D fingerprint plots. The computed C–N stretching vibration of the imidazole ring is observed at 1498, 1233, and 1064 cm−1. The HOMO is located on 4‐methylimidazole moiety of 5MIC molecule. Densities of state are used to find out the molecular orbital compositions of the 5MIC molecule. Mulliken analysis shows that the C13 (−0.86) atom has the lowest negative charge. The MEP surface color coded of 5MIC lies between 7.950 e−3 and −7.950 e−3. The 5MIC molecule has four types of intermolecular transitions. The first‐order hyperpolarizability (β) value of 5MIC molecule is 5.48×10−30 esu. The 5MIC crystal is thermaly stable up to 146 °C. The photoluminescence emission is observed from 400 to 600 nm. The 5MIC crystal shows SHG characteristics.

The Effect of Different Sludge Pretreatment Methods on Microalgae Performance and the Release of Pollutants in Hydrolysis Acidification Solutions

Waste-activated sludge disposal has now become a serious global problem. After pretreatment, sludge was hydrolyzed and acidified to release nutrients. The effects of different sludge pretreatments on microalgal growth and contaminants in a hydrolysis acidification solution were compared. Alkalinization (NaOH), ultrasound (US), and combined pretreatment techniques (US-NaOH) all promoted contaminants’ release from the sludge by triggering microbial cell wall rupture and extracellular polymer dissolution. The organics released from the pretreated sludge were more readily and rapidly consumed due the presence of abundant microorganisms. The US group was more capable of releasing contaminants than the NaOH group, while the US-NaOH group overrode both. The growth characteristics, photosynthetic performance, and effluent treatment properties of Chlorella were observed in all group. In the untreated group, Chlorella exhibited higher algal density, maximum photochemical quantum yield, and effluent treatment capacity. The results demonstrated that sludge pretreatment could facilitate the release and rapid consumption of pollutants. Additionally, the NaOH pretreatment could remove the refractory organics to a higher degree, and could also accumulate more photosynthetic pigments. This study demonstrated the feasibility of Chlorella being used in practical scenarios such as hydrolytic acidification solutions for different sludge treatment methods, providing data for wastewater treatment and resource utilization.