Pure Phase Research Articles

Phase evolution of nanocrystalline Mn-based oxides screened under different calcination temperatures using different precursors for proficient application in near infrared pigmentation

We examined how different calcination temperatures and precursors affect the formation of Mn-based oxides. The formation of these oxides was influenced by both the temperature (400–––1000 °C) and the type of precursors used (MnCl2·4H2O, MnCO3, MnO2, and KMnO4). When MnCl2·4H2O was calcined at 800 and 1000 °C/3h, we obtained pure tetragonal Mn3O4 phase materials. Calcining MnCO3 at 600 and 1000 °C resulted in cubic Mn2O3 and tetragonal Mn3O4 phase materials, respectively. Heating commercial MnO2 powder at 600 and 800 °C transformed it into cubic Mn2O3 phase materials. At 400 °C, the tetragonal MnO2 phase remained, but at 1000 °C, mixed Mn3O4 and Mn2O3 phases formed. Calcining KMnO4 at 1000 °C/3h led to the formation of δ-MnO2 materials. The morphological features of Mn2O3 and Mn3O4 materials exhibited different sizes and shapes, including nanostone-like, nanorod-like, and nanoflakes morphologies. The thermal analysis revealed significant differences in weight loss and thermal events, including exo and endothermic peaks. The Raman spectra and UV–Vis DRS measurements data support the formation of Mn-based oxides. The highest NIR reflectance for the various synthesized materials of Mn3O4 phase indicates a reflectance of 68 % in the solar region and 91 % in the color pigment region.

Comprehensive investigation into the influence of oxygen vacancies on the ferroelectric properties of spin coated bismuth ferrite thin films

Abstract Bismuth ferrite (BFO) is a prime candidate for room-temperature magnetoelectric coupling and multiferroic applications. The rhombohedral R3c phase of BFO is the source of many properties, but the phase purity and oxygen vacancies are still the biggest obstacles to its real-world application. Considering these facts, the present work investigates the effects of oxygen vacancies on the functional properties through manipulation of drying temperatures of spin-cast films, especially at temperatures around 280 °C, where both the secondary phase and oxygen vacancies are prevalent. One of the biggest sources of oxygen vacancy is bismuth volatilisation and our work deals with the situation head-on uncovering the effect of bismuth volatilisation on functional properties. The structural properties were studied using X-ray diffraction (XRD), and deeper insights into the surface topography of the samples were obtained using AFM imaging. The electrical and dielectric characteristics help distinguish and analyse the samples in terms of the presence of resistive switching. PUND studies were performed to determine the ferroelectric properties of the samples. A fifty percent reduction in the oxygen vacancies in the presence of secondary phases was observed when compared with the phase-pure sample, as shown by the XPS analysis. Deeper insights were provided into the valence band spectra by first-principles studies. This work shows that phase purity may not be the singular condition for enhancing functional properties, and fine-tuning the presence of secondary phases and oxygen vacancies may be the way forward. The ferroelectric polarisation in one of the samples exhibits a notably higher value when using chemical solution deposition methods, making it a promising candidate for memory devices.

Crystallization of Y3Fe5O12 thin films on silicon photonic waveguides using CO2 laser annealing

We report the local crystallization of Y3Fe5O12 (YIG) thin films grown on Si substrates, and SOI waveguides by CO2 laser annealing (LA). The effect of laser power and oxygen pressure on the crystal structure of YIG films was systematically studied. Laser power dominated the YIG film crystallinity, while oxygen partial pressure during LA strongly influenced the crystal grain size and magnetic anisotropy. Fully crystallized YIG thin films with pure garnet phases were fabricated by LA. The refractive index n and extinction coefficient k were comparable to thin films fabricated by rapid thermal annealing (RTA). Propagation loss measured at 1550 nm wavelength on YIG/SOI waveguides and YIG/SiN ring resonators were comparable to RTA annealed films, promising device development for silicon photonics.

Separation and purification of Ag and Se via vacuum thermal decomposition-volatilization of Ag2Se

In this study, theoretical and experimental investigations of the green separation and purification of Ag and Se from Ag2Se are conducted under vacuum. The vacuum separation theory calculation results indicate that the vapor pressure of Se is significantly higher than those of Ag and Ag2Se. Furthermore, the separation coefficient of the Se-Ag binary system is in the range of 104–105, and the Se content in the vapor phase exceeds 99.99 wt%. In contrast, the theoretical calculation results of vacuum thermal decomposition show that Ag2Se decomposes to Se2 (g) and Ag (l) at 1326.74 and 1488.21 K when the pressures are 1 and 10 Pa, respectively. The vacuum separation and purification experiments demonstrate that the purity of Se in the volatiles reaches 97.22 wt% at 1523 K, 50 Pa, and 480 min, and the main phase is the pure Se phase. Moreover, the purity of Ag in the residue reaches 91.88 wt%, and the main phase is the pure Ag phase. The vacuum thermal decomposition-volatilization proposed in this study can achieve environmentally friendly, short separation and purification of Ag and Se in Ag2Se.

Mixed N,O-donor Directed Blue Emissive Nano-dispersed Mesoporous Mn(II)-MOF:Dual Sensing Probe for Recyclable and Ultrasensitive ppb-Level Recognition of TNP and Cr(VI)-Oxoanions.

A new mesoporous Mn(II)-MOF [Mn2(phen)2(nia)2]∞ with 4-c uninodal net topology and reiterating rectangular channels in its cargo-net like extension was synthesized using π-conjugated phenanthroline (phen) and syn-syn bridging 5-nitroisopthalic acid (nia) linkers. The MOF (1) exhibited phase purity, uniform morphology, photo and thermal stability, and robustness; duly triggered by the exceptional framework rigidity via intermolecular H-bonding and interlayer π-π stacking interactions. The bright-blue luminescence of the MOF nano-dispersion was explored for sensitive, specific and ultrafast detection of trinitrophenol (TNP) with extremely low LOD (90.62 nM), high KSV (18.27 × 104 M-1) and Kq (4×1014 M-1s-1). The vapor-phase TNP sensing was also accomplished. Additionally, 1 served towards discriminatory, aqueous-phase monitoring of Cr(VI)-oxoanions, depicting LODs: 36.08 and 35.70 ppb; KSV: 3.46×104 and 4.87×104 M-1; Kq: 3.26×1013 M-1s-1 and 4.31×1013 M-1s-1;and response time: 32 and 40s for CrO42- and Cr2O72- respectively. The quenching mechanisms (i.e., RET, PET, IFE, weak interactions, collisional quenching and π···π stacking) was explained from several experimental investigations and theoretical DFT calculations. The recyclable sensing events and quantification from complex environmental matrices with admirable recovery rates and high KSV (13.02-22.44 × 104; ~6.31-10.98×104 and ~6.60-11.42 × 104 M-1 for TNP, CrO42- and Cr2O72-) undoubtedly advocated the consistency of the probe.

Photocatalytic degradation of methylene blue using chitosan/NiO nanocomposite: A comprehensive exploration

The present research work aims to illustrate the potential power of chitosan nanoparticles and chitosan/nickel oxide (NiO) nanocomposite for the photocatalytic degradation of methylene blue (MB). Initially, chitosan nanoparticles and chitosan/NiO nanocomposite were prepared using ball milling technique, focusing on the theory of top-down preparation. It was observed that, the as-prepared chitosan/NiO nanocomposite exhibited spherical shape with small size. Meanwhile, chitosan nanoparticles were prepared with irregular shape as depicted from TEM analysis. XRD affirmed the pure phase and crystalline structure of chitosan nanoparticles as a result to the observation for two peaks at 11.3o and 20.11o. New characteristic peaks at 35.3o, 38.5o, 49o, and 63o were noticed owing to the presence of NiO blended with chitosan nanoparticles. The estimated values of optical band gap energy for chitosan nanoparticles and chitosan/NiO nanocomposite are (3.6 eV, 3.5 eV), respectively. The photocatalytic degradation of MB dye employing chitosan nanoparticles and chitosan/NiO nanocomposite achieved 21 % and 96.1 %, respectively. The enhancement of photocatalytic efficiency of MB dye was mainly attributed to the potential effect of NiO nanoparticles. The findings also demonstrated that the photocatalytic performance of both chitosan nanoparticles and chitosan/NiO nanocomposite was pH, time, and catalyst doses dependent and obey Langmuir-Hinshelwood model. The photocatalytic activity of chitosan/NiO nanocomposite lost 14.9 % of its performance after first two cycles. Therefore, chitosan/NiO nanocomposite has emerged as a pioneering agent in sustainable water treatment, promising a transformative approach to combat water pollution. This study can guide future research, industry practices, and policy decisions towards a future where water treatment is synonymous with environmental harmony and innovation.

Spontaneous time-reversal symmetry breaking by disorder in superconductors

A growing number of superconducting materials display evidence for spontaneous time-reversal symmetry breaking (TRSB) below their critical transition temperatures. Precisely what this implies for the nature of the superconducting ground state of such materials, however, is often not straightforward to infer. We review the experimental status and survey different theoretical mechanisms for the generation of TRSB in superconductors. In cases where a TRSB complex combination of two superconducting order parameter components is realized, defects, dislocations and sample edges may generate superflow patterns that can be picked up by magnetic probes. However, even single-component condensates that do not break time-reversal symmetry in their pure bulk phases can also support signatures of magnetism inside the superconducting state. This includes, for example, the generation of localized orbital current patterns or spin-polarization near atomic-scale impurities, twin boundaries and other defects. Signals of TRSB may also arise from a superconductivity-enhanced Ruderman-Kittel-Kasuya-Yosida exchange coupling between magnetic impurity moments present in the normal state. We discuss the relevance of these different mechanisms for TRSB in light of recent experiments on superconducting materials of current interest.

Effective degradation of tetracycline under visible light by microwave-assisted reflux synthesis of ZnO/MoS2/rGO ternary nanocomposites

ZnO@MoS2 and conducting rGO based ternary nanocomposites were synthesized by a bottom-up microwave-assisted reflux method and effectively investigated for the photocatalytic degradation of tetracycline hydrochloride (TCH) antibiotic. The XRD, EDAX and XPS results corroborates the formation of nanostructure composite with high phase purity. The ZnO nanorods are well grafted on the curled configuration of layered MoS2 and thin surfaced rGO sheets as visualised from HR-TEM analysis. Upon addition of rGO, there is a significant decrease in the bandgap and improved visible light response in the ternary nanocomposites is elucidated by UV–visible Diffuse Reflectance Spectroscopy (UV-DRS) analysis. The suppression in photo-induced electron/hole pair recombination and allowing easy charge transport of ZnMG-50 were evidenced from photoluminescence (PL) and photo-electrochemical impedance (photo-EIS) spectroscopy. From BET and BJH analysis, the enhancement in surface area and pore volume by loading of rGO (SBET = 264.794 m2/g and 0.548 cm3/g). The optimized ZnMG-50 nano-photocatalyst possess a superior photocatalytic performance with higher removal efficiency of 92.18 % was achieved at pH level 10, catalyst dosage 40 mg and TCH concentration 20 ppm within 180 min under illumination. The degradation process compiles a pseudo-first order reaction with a kinetic rate constant of 0.01365 min−1. The nonstop generation of hydroxyl (˙OH) and superoxide (O2˙-) reactive species were beneficial for free electrons in the active participation, which remains as a core factor in the degradation process. The detailed study on ZnMG-50 nanocomposite substantiated to be an efficient noble metal-free synthetic catalyst for enhanced photocatalytic degradation of antibiotics.

Earth-abundant quaternary chalcogenide copper zinc tin sulfide-based nanocomposites CZTS-gCN and CZTS-GO (graphene oxide) as photocatalysts for degradation of methylene blue

This study explores the potential of Cu2ZnSnS4 (CZTS) as an environmentally friendly and nontoxic semiconductor photocatalytic material with a narrow band gap. The research focuses on investigating, photocatalytic degradation of Methylene Blue (MB) using CZTS-based nanocomposites prepared through hydrothermal approach. The experiments conducted in this study aim to determine the kinetics of photodegradation and adsorption of MB. Several models are applied to the experimental data to understand the underlying principles governing photocatalysis. The CZTS-gCN and CZTS-GO nanocomposites are thoroughly characterized using various analytical techniques such as X-ray diffraction for phase purity and crystallite size, Scanning Electron Microscopy, and other characterization are also employed to observe the morphology, phase structure, optical band gap, recombination of charge carriers The study discusses a potential method for enhancing the photocatalytic performance of the CZTS nanocomposite under light conditions. The photodegradation rate of MB dye is evaluated, showing a remarkable 64% degradation.

CuO nanoflowers: Multifaceted implications of various precipitating agents on rectification behaviour

In order to achieve the best possible use of traditional energy resources for the preservation of the environment, semiconductor-based optoelectronic devices are one of the most intriguing methods for converting light energy into electrical energy. CuO has been extensively explored as a material for energy conversion and the development of photo-detectors due to its notable characteristics among other metals, especially its non-toxicity, abundance, high efficiency, electrochemical stability and low cost/promising photodiode. However, some drawbacks limit its practical application in white light and photo-detector, including the rapid recombination rate of photo-generated electron-hole pairs and destitute response to visible light. As a result, several strategies have been developed from an optoelectronics perspective to eradicate these deficiencies and make an effort to enhance CuO photodiode activities. In this research work, the electrical characteristics and rectification behaviour of CuO with various precipitating agents have been examined. The CuO nanoparticles can be synthesized by co-precipitation technique prepared with different precipitants. Through this research, several parameters, such as the structural, functional, morphological, optical and electrical characteristics, were investigated by changing the precipitants. The functional group formation of pure CuO phase was confirmed by FT-IR studies. UV–Vis absorption measurements indicate that the band gap of the CuO nanoparticles was ranging from 2.40 to 2.85 eV. As a diode, CuO/p-Si exhibits a non-ideal behaviour and under light conditions with Na2CO3 precipitant, the better ideality factor is about 2.35. The barrier height is determined by the thermionic emission theory to be 0.77 and 0.79 eV in the dark and light conditions respectively.

Optimizing the synthesis of ZnFe2O4 through chemical and physical methods: effects of the synthesis route on the phase purity, inversion, and magnetic properties of spinel zinc ferrite

In this work, ZnFe2O4 ferrites were prepared by chemical (coprecipitation) and ceramic (ball-milling) methods. The effects of the synthesis route on the phase purity, crystallinity, particle size distribution, and magnetic properties were investigated to identify the most appropriate conditions for the synthesis of high-quality ferrites. The samples were examined by x-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and Mössbauer spectroscopy. The XRD patterns revealed that a high-purity spinel phase was obtained by coprecipitation at pH ≥ 7 by calcining the pristine powder at T ≥ 900 °C, whereas a single spinel phase was obtained at T ≥ 700 °C in the ball-milling method. The crystallite size of the spinel phase exhibited general increasing trends with the increase of the pH value under the same heat-treatment conditions and with the increase of the calcination temperature. Additionally, the mean physical particle size exhibited an increasing trend with the increase of the calcination temperature. The VSM measurements revealed a noticeable degree of inversion in the spinel ferrites prepared by coprecipitation (exhibiting the highest degree at pH = 10) and an insignificant degree of inversion in the spinel ferrites prepared by the ceramic method. However, calcining the powder exhibiting the highest degree of inversion (prepared by coprecipitation at pH = 10) at 1100 °C resulted in ordering the zinc ions at tetrahedral sites of the spinel structure. Mössbauer spectra for representative zinc ferrite samples prepared by the two methods revealed a major central doublet (with a small magnetic sextet corresponding to the α-Fe2O3 phase in the sample at pH = 7). The hyperfine parameters of the doublet observed in the Mössbauer spectra of the samples, and the corresponding magnetization behavior revealed a higher degree of ionic disorder in the spinel ferrite prepared by coprecipitation.

Electrochemical detection of antimalarial drug (Amodiaquine) using Dy-MOF@MWCNT composites to prevent erythrocytic stages of plasmodium species in human bodies

Herein, we report on fabrication of dysprosium-based metal–organic framework (Dy-MOF)@multiwalled carbon nanotubes (MWCNT) composites modified with glassy carbon electrode (Dy-MOF@MWCNT/GC) as a working electrode for Antimalarial drug detection. Dy-MOF@MWCNT composites was prepared by sonochemical process along with ultrasonication. The composite structure, phase purity, morphology and composition of the composites were confirmed by X-ray diffraction, Scanning electron microscope, and X-ray photoelectron spectroscopy. Further, Dy@MWCNT composites were deposited on a glassy carbon electrode by drop casting method, and used as an electrode material to efficiently detect Amodiaquine (ADD) by electrochemical techniques such as CV and DPV. The as-prepared Dy@MWCNT composite material showed the oxidation peak current of ADD to be ∼ 60 % higher than other unmodified GC electrodes and showed a low charge transfer resistance (R ct) of 24 Ω. The Dy@MWCNT provided a broad linear range of 0.4 to 20 µM with a limit of detection of 0.377 μM and sensitivity of 1.817 μA.μM−1 for the detection of ADD. According to the pH study, the amount of electrons and protons involved in the electrochemical processes of ADD was calculated and a plausible mechanism for ADD electro-oxidation was proposed. Thus, the prepared sensor exhibited practical usefulness by determining the ADD drug in human urine samples. Hence, the results shows that the Dy@MWCNT- modified sensor has good electrocatalytic activity for the redox of ADD.

Synthesis of TiO2 nanoparticles using red spinach leaf extract (Amaranthus Tricolor L.) for photocatalytic of methylene blue degradation

ABSTRACT Textile industry waste such as methylene blue can pose a serious threat to health and ecosystems. One solution to overcome this problem is to utilize photocatalytic technology using TiO2 semiconductors. This research aims to make green synthetic TiO2 nanoparticles (NPs) using red spinach (Amaranthus Tricolor L.) leaf extract and used for photodegradation of methylene blue. Extraction of red spinach leaves showed that 30 min and a temperature of 95°C showed the highest phenolic content. In this research, several phenolic compounds were also identified in red spinach extract. For TiO2 NPs, the X-ray diffraction results show that TiO2 has a pure anatase phase. Electron microscope results show that TiO2 has the shape of agglomerated spherical clusters. The particle size distribution shows that TiO2 has an average size range of 77–90 nm. The methylene blue photodegradation showed that TiO2 had an efficiency of 90.36% for 180 min, higher than commercial TiO2 Evonic. This result can be attributed to the small particle size and broadband spectra so that photocatalysis is more effective.

Crystalline MnCO3@Amorphous MnOx Composite as Cathode Material for High-Performance Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (RAZIBs) have received extensive attention because of their advantages of low cost, high safety, and nontoxicity. However, problems such as dissolution of the active cathode material, dendrites/passivation of the zinc anode, and slow reaction kinetics hindered their further applications. In this work, a crystalline/amorphous composite-type material composed of crystalline MnCO3 and amorphous MnOx was prepared and used as the cathode material for RAZIBs. The MnCO3@amorphous MnOx (MnCO3@A-MnOx) composite possesses the merits of both the pure crystalline phase of MnCO3 and the amorphous phase of MnOx, which can deliver better electrochemical performance than the corresponding single component in repeated cycles. In addition, crystalline MnCO3 undergoes a complex phase transition to the active MnO2 during the first charge process, providing the composite with a stable structure and additional electrochemical capacity. The electrochemical measurement results indicate that the MnCO3@A-MnOx electrode can display high reversible discharge capacity at 0.1 A g-1, excellent rate performance at 5.0 A g-1, and long cycling stability over 2000 cycles, showing great potential as a cathode material for high-performance RAZIBs.

Cool green-emissive Y2Si2O7:Tb3+ nanophosphor: auto-combustion synthesis and structural and photoluminescence characteristics with good thermal stability for lighting applications.

A cheap, versatile, sustainable and energy-efficient gel-combustion method was applied to develop a series of green-emitting down-converted Y2Si2O7:Tb3+ (YPS:Tb3+) nanophosphors. Employing XRD-based Rietveld refinement approach, the phase purity and crystallographic evaluation of the produced phosphor were conducted, revealing a triclinic crystal with P1̄ space group. EDX and TEM analyses were performed on the synthesized samples to determine their elemental composition and morphological properties. Diffuse reflectance spectra yielded 5.61 eV and 5.79 eV optical energy band gaps for the host and the optimized (0.04 mole of Tb3+) sample, respectively. UV light has the ability to excite the nanocrystalline phosphor in an efficient manner, leading to significant luminosity qualities attributed to the radiative relaxation of 5D4 → 7FJ (J = 6, 5, 4, 3). The bi-exponential decay function was derived by the PL decay curves. With an activation energy of 0.2206 eV, the Y1.96Si2O7:0.04Tb3+ phosphor exhibits good thermal quenching capabilities. Improved photometric attributes including CIE coordinates, CCT and color purity confirmed the green glow, indicating a strong competitor for cool-green emission in lighting applications.

One‐Step Synthesis of Phase‐Controlled Co2P Nanoparticles as an Electrocatalyst for Hydrogen Evolution Reaction

AbstractCobalt phosphides have been investigated as potentially useful electrocatalysts for accelerating hydrogen evolution. Cobalt phosphide electrocatalysts are synthesized in a single step at varied phosphating temperatures (350, 400, 450 °C) via the gas phase approach. Synthesized at a phosphating temperature of 350 °C, Co2P (CP‐350) transforms into a mixed phase that contains both Co2P and CoP (CP‐400 and CP‐450) as the phosphating temperature goes up which is confirmed by XRD. CP‐350, CP‐400, and CP‐450 exhibited overpotentials of 181, 270, and 293 mV respectively with Tafel slopes of 112, 146, and 175 mV/dec. In contrast to CP‐400 and CP‐450, CP‐350 revealed superior hydrogen evolution reaction (HER) performance and stability for up to 12 h due to its pure phase (Co2P), high surface area (151 m2/g), and high electrochemical surface area (7.02 cm2) with low charge transfer resistance. According to our work, changing the phase and active surface area of transition metal phosphide catalysts can greatly increase their HER catalytic efficiency.

Lead-Free Semiconductors: Phase-Evolution and Superior Stability of Multinary Tin Chalcohalides.

Tin-based semiconductors are highly desirable materials for energy applications due to their low toxicity and biocompatibility relative to analogous lead-based semiconductors. In particular, tin-based chalcohalides possess optoelectronic properties that are ideal for photovoltaic and photocatalytic applications. In addition, they are believed to benefit from increased stability compared with halide perovskites. However, to fully realize their potential, it is first necessary to better understand and predict the synthesis and phase evolution of these complex materials. Here, we describe a versatile solution-phase method for the preparation of the multinary tin chalcohalide semiconductors Sn2SbS2I3, Sn2BiS2I3, Sn2BiSI5, and Sn2SI2. We demonstrate how certain thiocyanate precursors are selective toward the synthesis of chalcohalides, thus preventing the formation of binary and other lower order impurities rather than the preferred multinary compositions. Critically, we utilized 119Sn ssNMR spectroscopy to further assess the phase purity of these materials. Further, we validate that the tin chalcohalides exhibit excellent water stability under ambient conditions, as well as remarkable resistance to heat over time compared to halide perovskites. Together, this work enables the isolation of lead-free, stable, direct band gap chalcohalide compositions that will help engineer more stable and biocompatible semiconductors and devices.

Manufacturing of High Purity Cr2AlC MAX Phase Material and Its Characterization

AbstractPresent study discusses about a technique for producing high-purity Cr2AlC MAX phase materials and gaining insight into their thermal behavior for high-temperature applications. The research conducted involved synthesizing a pure layered ternary carbide Cr2AlC MAX phase material by mixing powders of Chromium, Aluminum, and Carbon and then subjecting them to two-step pressureless sintering process in argon atmosphere. First step involves the annealing of ball-milled mixture at 750 °C for 2 h followed by the second step in which the annealed mixture is subjected to heat-treatment at 1350 °C for 2 h. Analysis using XRD and Raman techniques revealed that the synthesized product consists of Cr2AlC phase, without any impurities. SEM studies confirmed that the Cr2AlC had a layered topography, while EPMA analysis indicated that the atomic percentage of Cr, Al, and C was consistent with the XRD phase analysis. XPS investigations confirmed the presence of Cr-C bonds representing Mn+1Xn of the MAX phase material. TG-DSC results showed an approximately 2% increase in weight. The Cr2AlC phase exhibited an endothermic pattern below 725 °C, an exothermic pattern above it, and did not decompose up to 1400 °C in vacuum environment. High-temperature XRD analysis at various temperatures also confirmed no formation of Al2O3 or CrO impurity compounds.

The Effect of Lewis Acid-Base Additive on lead-free Cs2SnI6 thin film prepared by direct solution coating process

Abstract Inorganic Cs2SnI6 perovskite has exhibited substantial potential for light harvesting due to its exceptional optoelectronic properties and remarkable stability in ambient conditions. The charge transport characteristics within perovskite films are subject to modulation by various factors, including crystalline orientation, morphology, and crystalline quality. Achieving preferred crystalline orientation and film morphology via a solution-based process is challenging for Cs2SnI6 films. In this work, we employed thiourea as an additive to optimize crystal orientation, enhance film morphology, promote crystallization, and achieve phase purity. Thiourea lowers the surface energy of the (222) plane along the ＜111＞ direction, confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy studies, and density functional theory calculations. Varying thiourea concentration enables a bandgap tuning of Cs2SnI6 from 1.52 eV to 1.07 eV. This approach provides a novel method for utilizing Cs2SnI6 films in high-performance optoelectronic devices.

Multi-walled carbon nanotube wrapped rare earth tungstate nanosheet composites for selective and rapid detection of sulfadiazine

Multi-walled carbon nanotube wrapped rare earth tungstate nanosheet composites are developed for the ultrasensitive and selective electrochemical detection of sulfa drug, sulfadiazine (SAN) as they exhibit high levels of toxicity towards public health and ecosystem. Here, we synthesized Gadolinium tungstate decorated with multi-walled carbon nanotubes (Gd2WO6/MWCNT) though hydrothermal processing and characterized by XRD, SEM, EDX, TEM, and EIS measurement to investigate the phase purity, morphology, and interfacial property. Gd2WO6 is a double perovskite that has high oxygen surface exchange kinetics and the MWCNT possesses high catalytic capability and a larger surface area contributes to the efficient sensing ability. The Gd2WO6/MWCNT possessed a great electrical conductivity owing to the synergism between the Gd2WO6 and MWCNT. The synergistic effect increases the surface area, ionic and electrical conductivity which increases the current response of SAN. Under optimum conditions, the Gd2WO6/MWCNT/GCE displays a broad linear of 0.01 – 671 µM and a LOD level of 2 nM (S/N ratio: 3) with a sensitivity of 0.371 µA µM cm−1. The analytical applicability of the proposed electrode modifier leads to a promising sensor for SAN detection in human urine and water samples with appreciable results.