UV Vis NIR Spectroscopy Research Articles

Synthesis, optical linear and non-linear characterization and metal ion sensing application of some novel thieno[2,3-b]thiophene-2,5-dicarbohydrazide Schiff base derivatives

Synthesized 3,4-Diaminothieno[2,3-b]thiophene-2,5-dicarbohydrazide (DTT) Schiff base derivatives newly were synthesized by attaching with different aldehydes, deposited in thin film form by thermal evaporation technique, and characterized by UV–Visible-NIR spectroscopy, FT-IR, NMR, and elemental analysis. It is revealed that compound 4 has the highest absorption peak intensity at 586 nm. The allied absorption, dielectric, and dispersion parameters have been calculated and discussed. The obtained results manifested that compound 4 and DTT have lower (1.92 eV), and higher (3.47 eV) energy band gap values, respectively, as a result of the conjugation number effect. The high nonlinear refractive index n2 and third-order nonlinear susceptibility χ(3) of these organic thin films are comparable with those of chalcogenide and oxide materials, making them promising for nonlinear optical systems. Compound 4 displays high sensitivity towards metal ion detection (ex. Cu+2, Ni+2, Fe+3, Mn+2, Pb+2, Co+2), suggesting its ability to be applied as a metal ion sensor and quantifying their concentration levels by means of a suitable calibration curve.

Impact of Side Chain Chemical Structure on Doping and Thermoelectric Properties of Oriented PBTTT Thin Films

AbstractIn this contribution, doping of oriented thin films is investigated for three PBTTT polymers bearing different side chains including linear alkyl ─(CH2)12─H, single ether ─(CH2)7─O─(CH2)4─H and alkyl‐siloxane ─(CH2)5─(Si(CH3)2O)2─Si(CH3)3 A combination of transmission electron microscopy, polarized UV–vis–NIR spectroscopy and transport measurements helps uncover the essential role of the chemical nature of side chains on the efficacy of the doping and on the resulting thermoelectric performances in oriented PBTTT films. Siloxane side chains help to reach record alignment level of PBTTT with dichroic ratio beyond 50 for an optimized rubbing temperature but they impede effective doping of PBTTT crystals with F6TCNNQ, resulting in very poor TE properties. By contrast, doping the amorphous phase of all three PBTTTs with magic blue (MB) results in excellent TE performances. Both, chemical nature of side chains and semi‐crystalline structure of the polymer determine the efficacy of doping. The use of siloxane side chains further impacts the scaling laws S ∝ σ−1/s between the Seebeck coefficient S and the charge conductivity σ. An unexpected s = 2 exponent is observed and tentatively attributed to the dimensionality of charge transport in the highly oriented mesophase of PBTTT.

Fabrication of chitosan coated bentonite clay multifunctional nanosorbents from waste biomass for the effective elimination of hazardous pollutants from waterbodies: A fixed bed biosorption, mechanism, and mathematical model study

The anthropogenic activity and hasty fluctuating technologies have been responsible for the generation of massive effluent which is so hazardous due to the loading of several toxicants. While most industries usually discharge it directly into the environment resulting in harsh damage to the ecology/public security. Therefore, it is critical to treat with a sustainable/cost-effective technique. Here, a new route of fabrication of chitosan-coated activated natural bentonite clay (CCANBC) bionanocomposites/bionanosorbents from waste biomass has been developed. Their potential application for the simultaneous removal of Ni2+ and Eosin Y from wastewater were investigated. The effective parameters like concentration (10–30 ppm), flow rate (2–4 mL/min), and bed height (0.5–1.5 cm) were inspected. The bionanosorbents were characterized by FTIR-ATR, XRD, FESEM, TGA, and BET analysis. Additionally, the effluents were explored by AAS and UV–vis-NIR spectroscopy. According to the findings it has been stated that the CCANBC bionanosorbents possessed significant dynamic edges, greater crystallinity (94.27 %), and higher thermal stability. They have exhibited a remarkable 2D honeycomb-like mesoporous microstructure with substantial specific surface area (19.29 m2/g). These outstanding features could be responsible for the dramatic adsorption enactment around 186.42 and 238.37 mg/g for Ni2+ and Eosin Y. The obtained data were evaluated by several mathematical models for better understanding the experimental BTC curve, reaction mechanism, and adsorption isotherm.

Effect of oxygen vacancies on enhancing the photo-catalytic activity, photo-luminescence and electronic structure properties of nanostructured Y-doped CeO2

The exceptional characteristics of CeO2 and Ce1-xYxO2 (x = 0.03, 0.05 and 0.07) nanoparticles were reported in the manuscript supporting that Y3+replaces Ce3+/Ce4+leads to oxygen vacancies formation. The results of XRD measurements revealed FCC structure of decreased crystallite size of CeO2 with improved crystallinity. To investigate the surface morphology, HRTEM and SAED patterns were performed. EDX analyses were undertaken to discuss the elemental and compositional characteristics. The absorption spectra using UV–Vis–NIR spectroscopy were analyzed and red shifted absorbance was found to enhance with decreasing band gap values for increased Y doping. The Photoluminescence spectra depicted various emissions representing the development of various defects and oxygen vacancy with incorporation of Y content in the lattice with CCT values below 4000 K to be classified as warm yellow light for indoor applications. The development of oxygen vacancies in the CeO2 lattice was further supported by XPS measurements for core levels Ce 3d, O 1s and Y 3d. Furthermore, the XPS measurements also reported the valence states of elements, Ce with 3+ and 4+, Y with 3+ and O with 2- along with charged oxygen vacancies. The photo-catalytic analysis revealed that Y-doped CeO2 nanoparticles show better degradation using a variety of characterization. A degradation mechanism that illustrates the impact of oxygen vacancies created by Y-doping on the photo-degradation process has been proposed. The novelty of Y-doped CeO2 nanoparticles stems from their improved photo-catalytic activities, which are linked to structural changes and the formation of oxygen vacancies. This doping considerably affects the electrical structure, resulting in better light absorption and less electron-hole recombination. The detailed outcomes of present study suggested the use of Y-doped CeO2 nanoparticles in optoelectronics, spintronics devices and photo-catalyst applications.

The impact of proton ion irradiation on Se70Te20In10 thin films: Linear and non-linear optical properties for photonic applications

The examination of the linear and non-linear optical features was conducted on amorphous ternary Se70Te20 In10 thin films, which were exposed to proton irradiation energy of 3 MeV at varying fluences of 5×1013, 5×1014, 5×1015 and 5×1016 ions/cm2. The bulk sample was produced using the melt quenching method, and subsequently, thin films were obtained through electron beam evaporation. Calculations of linear and non-linear optical parameters were carried out based on transmittance and reflectance data acquired from UV–Vis–NIR spectroscopy spanning 300–2500 nm. Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) confirmed an amorphous phase in the films. The optical parameters showed strong dependency on the proton radiation fluence. In addition, the existence of minima or maxima for a number of parameters at a fluence of 5×1014 ions/cm2 showed that this was the optimum fluence. The linear and non-linear properties showed that the sample have potential applications in photonic devices.

Unveiling the influence of synthesis techniques on crystallite size of CuInS2 nanostructures

Copper indium disulfide (CuInS2) nanostructures are synthesized by wet precipitation and sol–gel techniques. The high-resolution transmission electron microscopy (HRTEM) analysis exhibits nanorods (NR) and nanocubes (NC) of CuInS2 resulting from wet precipitation and sol–gel methods, respectively. Their characterizations are accomplished by UV–vis-NIR spectroscopy, dynamic light scattering (DLS), and x-ray diffraction (XRD) techniques. The particle size is obtained from HRTEM, UV–vis-NIR, and DLS analyses. Average crystallite size is estimated via Scherrer’s method (graphical and analytical), Monshi-Scherrer method, Williamson–Hall relations (uniform deformation, uniform stress deformation, and uniform deformation energy-density models), size-strain plot method, and Halder-Wagner relation using XRD profile which is also compared with as-obtained particle size. Moreover, the XRD pattern reflection peaks are used to assess more accurately energy density, lattice stress, and microstrain values. The results affirm NR have higher crystallite size (∼22 nm) than NC (∼16 nm). The outcomes demonstrate outstanding agreement of predicted average crystallite sizes using the different approaches.

Synthesis and characterization of ZnO nanoparticles prepared by green routes: controlling morphologies by maintaining pH

The synthesis of metal oxide semiconductor nanoparticles has attracted much attention in recent past. Nanoparticles are broadly used in solar energy conversion, catalysis, varistors, gas sensors, and non-linear optics, etc. Due to their wide band gap properties, zinc oxide nanoparticles are widely used in numerous applications. Zinc oxide nanoparticles have a wide band gap of approximately 3.3 eV. In this work, we have reported synthesis and characterization of ZnO nanoparticles having rod-like, spherical and flower-like structures. We have used zinc acetate dehydrate [Zn(CH3COO)2. 2H2O] and aqueous extract of Dahlia Pinnata leaves and deionized water. Dahlia Pinnata leaves extract has not been previously used to prepare ZnO NPs. It serves as a reducing and capping agent. We have analyzed the presence of chemicals in the extract using FTIR, Raman and NMR spectroscopy techniques. It is found that the unique morphology of ZnO NPs flower-like structures, enhances it's sensing properties in comparison to the spherical ones. We have used UV–vis-nir spectroscopy, x-ray diffraction (XRD), Fourier Transform Infrared Microscopy(FTIR), and Scanning Electron Microscope (SEM) analysis and have explored the opto-electronic properties of ZnO nanoparticles and have correlated with their structural and morphological properties.

Magneto-fluorescent core–shell Sr0.8La0.2Fe11CuO19 @ CQDs for the detection of metal ions

The fabrication of a sensor based on a core–shell structure of Sr0.8La0.2Fe11CuO19 @ CQDs was effectively achieved through the combination of high quantum yield carbon quantum dots (CQDs) with La-Cu doped M−type strontium hexaferrites (SLFCO HF). The structural, morphological, and spectroscopic information of the as-synthesized samples were characterized through X-ray diffraction (XRD), Raman spectroscopy (RS), Fourier transform infrared (FT-IR), energy dispersive X-ray (EDX), high-resolution transmission electron microscopy (HR-TEM), and UV–Vis-NIR spectroscopy. The magnetic properties were tested using a vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. HR-TEM confirmed the formation of a hexagonal core–shell sample at the nanoscale. Based on photoluminescence (PL) spectra and the CIE chromaticity map, the parent sample and core–shell structure of SLFCO/CQDs were found to have color coordinates corresponding to yellow-green emission. It was found that the core–shell sample has an increased light-absorption capacity, low photogenerated electron-hole recombination, high coercivity, small crystallite size, and showed good sensitivity towards the detection of Zn2+, Cd2+, and K+ ions. A high efficiency in detecting potassium (K+) ions with a limit of detection (LOD) of 15 ppm was observed. Moreover, the distinctive magnetism of CQDs @ SLFCO aided in the collection and recycling of the sensor.

Exploring the potential of bismuth-containing silicate borate glasses for optoelectronic devices and radiation protection

This study studied novel bismuth silicate borate glasses with different bismuth oxide (Bi2O3) concentrations for their optical and γ-radiation shielding capabilities. The glass samples were characterized using UV–Vis–NIR spectroscopy to determine their optical properties, including the optical absorption spectra, absorption edge, and optical band gaps. The FLUKA algorithm was used to determine the radiation shielding parameters in the energy range of 0.01–15 MeV. The results revealed that the optical absorption edge and intensity were influenced by the Bi2O3 concentration, with the highest absorption observed in the sample with 35 mol% Bi2O3. The direct and indirect optical band gaps decreased with adding Bi2O3 up to 15 mol%, then increased at 25 mol%, and then reduced to the lowest value at 35 mol%. The system's crystallite size grew as the amount of Bi2O3 in the sample increased, as revealed by XRD. With increasing Bi2O3 content, it was discovered that the mass attenuation coefficient (μm) and radiation shielding effectiveness rose. The effective atomic number (Zeff) values increased as Bi2O3 content grew. T0.5 values of the glass samples increased as the energy increased and decreased as the Bi2O3 concentration increased. These findings suggest that prepared glasses with high Bi2O3 concentrations have potential applications in radiation shielding and optoelectronics.

The further development of the borate nitrate family: Synthesis and characterization of Ag12(B9O18)(NO3)3 with unique isolated B9O18 clusters, 9B:6Δ3□:3(–)

Single crystals of a novel silver borate nitrate, Ag12(B9O18)(NO3)3 (1), were produced as a byproduct upon preparation of Ag3B6O10(NO3). 1 is hexagonal, (P63/m, a = 11.2896(3) Å, c = 11.6693(3) Å); its structure exhibits just a second example of unique [B9O18]9– nonaborate anions [9B:6Δ3□:3(<2Δ□>–)<3□>] which can be described as three triborate groups linked in a large cycle. As commonly observed among silver borates, the Ag+ cations exhibit strongly anharmonic vibrations which were described using Gram–Chariler series up to 4th order. 1 is characterized by single-crystal X-ray diffraction, variable-temperature powder X-ray diffraction, IR, Raman, and UV–vis-NIR spectroscopy, complex thermal analysis, and DFT calculations. The thermal expansion of 1 is slightly anisotropic (αa = 15.0, αc = 17.7 × 10−6 °C−1 at 200 °C). Upon heating, the compound decomposes with formation of metallic silver and another borate, AgBO2, which could be earlier prepared only at high oxygen pressure.

Substitution of an isovalent Te-ion in SnSe thin films for tuning optoelectrical properties

In present work, SnSe1-xTex thin films with varying Te concentrations were deposited on glass substrate through thermal evaporation technique. SnSe1-xTex thin films were characterized using X-ray diffraction (XRD), atomic force microcopy (AFM), X-ray photoelectron spectroscopy (XPS), UV–Vis NIR spectroscopy and room-temperature hall measurements technique. XRD patterns revealed that all the samples had a polycrystalline orthorhombic structure. Additionally, a low level of Te impurity improved the crystalline quality of the SnSe thin films. AFM images showed a noticeable alteration in the surface structure of the SnSe thin films caused by Te doping. UV–Vis NIR spectroscopy was employed to assess the optical characteristics of SnSe1-xTex thin films, revealing a variation in the optical band gap energy (Eg) between 1.75 and 1.89 eV, attributed to Te doping. The Hall effect measurement revealed n-type conductivity, and the carrier concentration decreased as the Te dopant concentration increased, corresponding to a decrease in antisite SnSe defects. The experimental findings suggest that adding a moderate amount of Te is a beneficial method for enhancing the optical and electrical properties of SnSe films. Furthermore, the Schottky device parameters of the Ag/SnSe1-xTex/Al:ZnO structure were established by analyzing the temperature-dependent Current-Voltage (I–V-T) characteristics through the thermionic emission current transport mechanism.

Theoretical DFT and experimental investigation of the effect of Co doping in electrochemically deposited ZnSe films

In this study, we examine the impact of introducing cobalt doping on the morphological, structural, optical, and electronic properties of ZnSe thin films produced by electrodeposition at room temperature. Characterization techniques, including X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and UV–Vis–NIR spectroscopy, were employed to analyze structural, morphological, and optical features. The developed films display a consistent and even distribution of grains with a cubic structure, showcasing a preferred orientation along the (111) axis. The calculated crystal size was estimated to be around 80 nm. The elemental composition of the film aligns with the synthesized deposition of elements. The introduction of cobalt resulted in enhanced optical properties and reduced energy bandgaps in the films. Concurrently, theoretical studies using the FP-LAPW approach in density functional theory were conducted, focusing on structural, electronic, and optical properties of cobalt-doped ZnSe at different concentrations (2 %, 4 %, 6 %). Theoretical findings demonstrated a substantial decrease in the bandgap, aligning well with the experimentally determined value of 2.72 eV. This coherence between theoretical predictions and experimental observations highlights the effectiveness of cobalt doping in influencing the optical characteristics of ZnSe thin films.

Self‐Doped Mixed Ionic‐Electronic Conductors to Tune the Threshold Voltage and the Mode of Operation in Organic Electrochemical Transistors

AbstractOrganic mixed ionic‐electronic conductors with tunable doping, low threshold voltages, and air stability are crucial for bioelectronic applications. A homopolymer based on an alkoxy thiophene monomer and its copolymer with a thiophene carrying ethylene glycol side chains are synthesized and converted to self‐doped conjugated polyelectrolytes, P3HOTS‐TMA+, and P3HOTS‐TMA+‐co‐P3MEEET. The self‐doping occurs during the conversion to polyelectrolytes. Both polyelectrolytes show high electrical conductivity without any external dopants. UV–Vis–NIR spectroscopy and spectroelectrochemistry confirm excellent air stability of the doped state. In an organic electrochemical transistor (OECT), the P3HOTS‐TMA+ operates in depletion mode, while P3HOTS‐TMA+‐co‐P3MEEET exhibits accumulation mode of operation with low threshold voltage, both showing fast response times. On the other hand, the non‐doped homopolymer, P3MEEET, shows a high negative threshold voltage in accumulation mode. Thus, copolymerization with the self‐dopable monomer changes the mode of operation as well as the threshold voltage substantially. Ultraviolet photoelectron spectroscopy reveals a considerable reduction of the hole injection barrier for the self‐doped system P3HOTS‐TMA+. Mott‐Schottky analysis shows reduction in charge carrier concentration in the copolymer compared to the homopolymer. Thus, the copolymerization strategy with a self‐dopable monomer is an efficient tool for tuning the degree of doping leading to low threshold voltage in OECTs.

Optical behaviour of magnetron sputtered nano-hilled TiN coatings

Cylindrical magnetron sputtered TiN thin films have been grown on glass (G) and quartz (Q) substrates to examine optical properties under two flow conditions: increasing nitrogen flow rate (1 → 35 sccm): (I) and decreasing nitrogen flow rate (35 → 1 sccm): (D). The optical properties of the film are characterized using UV–Vis-NiR spectroscopy, spectroscopic ellipsometry, and photoluminescence studies. Films deposited under both parameters exhibited excellent UV-restriction properties. Nano-hilled topography of the film contributed to multiple reflections and scattering of incident light on both quartz and glass specimens. Clustering of nano-particles in G(D) specimen increases the light interaction and absorption within the film leading to higher absorbance and lower transmittance properties compared to G(I). TiN-Quartz specimen displayed better UV absorbing properties compared to TiN-Glass as confirmed through ellipsometry studies. lack of phonon-related transitions in Tauc's plot indicated the involvement of direct allowed transitions.

The figure of merit improvement of (Sn, Co)–ZnO sprayed thin films for optoelectronic applications

Nanocrystalline zinc oxide (ZnO) has garnered significant attention from researchers and industries due to its superior properties as an optoelectronic material, particularly in solar cells as a transparent electrode. Doping, especially with tin (Sn) and co-doping with tin and cobalt (Co), can refine its optoelectronic properties. In this manuscript, we report on the optoelectronic properties of undoped ZnO thin films, as well as those doped with Sn and/or Co, elaborated using a simple chemical pneumatic spray pyrolysis method on glass substrates. A 1 % Sn doping concentration was used, with Co doping concentrations of 0 %, 0.5 %, and 1 %. The effects of Sn and/or Co doping concentration on the structure, morphology, optical, and electrical properties of nanocrystalline ZnO were studied using X-ray diffractometer (XRD), Raman spectroscopy, Field emission scanning electron microscopy (FESEM), UV–Vis–NIR spectroscopy and Hall effect measurements. All the films studied exhibit wurtzite ZnO structures with a predominant (002) orientation and no secondary phase, as confirmed by X-ray diffraction (XRD) analysis. The Raman spectroscopy also reveals the presence of a wurtzite structure in all the films. The FESEM images reveal the kind and concentration of the dopants significantly influenced the surface morphology of the films. The elemental analysis with energy dispersive X-ray analysis (EDS) analysis successfully detected the doping of Sn and Co. The analysis of UV–Vis spectroscopy provide that the optical band gap for the undoped ZnO film is 3.25 eV. This band gap increases upon doping and co-doping, reaching a peak value of 3.30 eV for the Sn:Co (1 %:0.5 %) co-doped ZnO film. The ZnO film shows an improvement in the electrical resistivity upon doping and co-doping with low resistivity value of 1.95 × 10−2 Ω cm for the film (1%Sn, 0.5 % Co)–ZnO. The highest figure of merit (FOM) achieved is 1.41 × 10−4 Ω−1 for a ZnO thin film co-doped with (1 % Sn, 0.5 % Co). The existence of (1 % Sn, 0.5 % Co) film with improved optical gap, low electrical resistivity and high FOM supports its use in transparent conductive oxide applications.

Gamma irradiated Er3+ ions doped Li2O–BaO–B2O3–P2O5 glasses: Structural, optical, and thermoluminescence glow curve analysis

Lithium barium borophosphate glasses doped with Er3+ rare earth ions are reported in terms of their physical, optical, structural, and thermoluminescence (TL) properties in this study. The melt quenching method was used to synthesize the glasses with varying concentration of the dopant (0.0, 0.2, 0.4 0.6, 0.8 and 1.0 mol%). A thorough analysis of physical characteristics, including their variation with erbium oxide, has been conducted. The amorphous phase of the as-quenched samples has been validated through X-ray diffraction patterns, while Fourier transform infrared spectroscopy confirmed the existence of different structural groups. UV–Vis–NIR spectroscopy at wavelengths ranging from 200 to 1100 nm has been utilized to investigate various optical properties. In the gamma dose range of 50 Gy to 10 kGy, the glass sample with 0.6 mol% of erbium concentration (LBPEr0.6) showed the maximum integrated TL intensity with an optimized heating rate of 5 °C/s and annealing temperature of 400 °C. The deconvolution of TL glow curves was done using the R-package “tgcd: Thermoluminescence Glow Curve Deconvolution" by employing the Kitis general order kinetics model. Chen's peak shape approach has been used to calculate the trapping parameters, including order of kinetics (b), shape factor (μg), frequency factor (s), and activation energy (E). The ideal thermoluminescence dosimeter characteristics showed that LBPEr0.6 glass has outstanding linearity, excellent sensitivity, minimal fading and good reproducibility over six cycles.

Structural, linear/nonlinear optical characteristics and radiation shielding effectiveness of Cu4O3/Cu2O dual-phase thin films: Influence of oxygen flow rate in reactive sputtering process

In the present work, we investigated the impact of oxygen flow rate on the structural, linear, and nonlinear optical characteristics while also evaluating the radiation shielding effectiveness during reactive radio frequency (rf) sputtering in the deposition of Cu4O3/Cu2O dual-phase thin films. Microstructural analysis revealed distinct changes with increased OFRs, switching from a Cu2O cubic structure phase to a Cu4O3 tetragonal structure phase. The XRD patterns revealed good crystallinity, and the crystallite size of the film reduced from 28 nm to 22 nm, and the microstrain exhibited an opposing trend as the oxygen flow rate increased. In contrast, investigating the optical properties of dual-phase Cu4O3 and Cu2O thin films using UV–Vis–NIR spectroscopy revealed intriguing trends in the absorbance spectra, absorption coefficient, and extension index. The apparent bandgap increases from 2.0 eV to 2.62 eV with increasing oxygen flow rates. In addition, nonlinear optical parameters, including the nonlinear refractive index n2 linear, nonlinear sensitivity (χ1 and χ3), and nonlinear absorption coefficient βc were calculated to demonstrate the applicability of these materials. The dual-phase structure of the films enhances their potential for effective radiation shielding. Our findings provide valuable insights into the design of properties of Cu4O3/Cu2O dual-phase thin films for applications ranging from photoelectric and nonlinear optical devices to radiation shielding effectiveness.

Defects induced SnOx-TiO2 nanocomposite thin films for improved visible light driven photocatalysis and photoelectrochemical applications

Advanced oxidative removal of organic pollutants from water bodies using nanoparticles of metal oxide photocatalysts is a concurrent hot topic. In the present study, SnOx-TiO2 heterogeneous nanocomposite thin film photocatalysts have been synthesized using SnO and TiO2 precursors by binder-free doctor blade technique. X-ray diffraction was used to confirm the presence of anatase TiO2 as a major phase at elevated temperatures. Raman spectra analysis confirmed phase transformation and defect induction. X-ray photoelectron spectroscopy was utilized to determine the purity and chemical condition of the synthesized thin films. The porous nature of the thin film surface was observed using field emission scanning electron microscopy. UV–Vis-NIR spectroscopy results showed a reduction of bandgap from 3 eV to 2.6 eV with enhanced light absorption. The superior oxygen evolution reaction, redox nature and charge carrier generation were demonstrated using photo-electrochemical techniques. Improved photoresponse of the photocatalysts was observed using chrono-amperometry technique. The superior visible light-driven photocatalytic activity of the samples was demonstrated utilizing cationic and anionic model pollutant dyes. The reusability of the catalyst is ensured through successive photodecomposition processes. These results show a facile fabrication of defects induced heterogenous nanocomposite photocatalyst thin films with improved visible light activity.

Comprehensive investigation of 2-methylquinolinium-5-sulphosalicylate monohydrate: Synthesis, characterization, multifaceted analysis of molecular structure, optical, and nonlinear optical properties

We introduce the synthesis and characterization of a novel molecular salt crystal, 2-methylquinolinium-5-sulphosalicylate monohydrate (MQSSA), obtained through an equimolar reaction between donors (D) and acceptors (A) employing crystal engineering principles. The resulting proton transfer complex, MQSSA, crystallized into a monoclinic crystal system with space group P21/C, as revealed by SCXRD analysis. Significant peaks observed in PXRD analysis confirmed the crystallinity and purity of the material. FT-IR and FT-Raman spectroscopy were employed to analyze various functional groups present in the molecule. UV–Vis-NIR spectroscopy provided insights into absorbance transmittance, lower cutoff wavelength, and optical band gap, suggesting it's suitability for diverse optical applications, while characteristic emission was identified using PL measurements. Thermal stability was assessed via TG-DTA and TG-DSC techniques. Nonlinear absorption coefficient (β), nonlinear refractive index (n2), and third-order nonlinear susceptibility (χ3) were quantified using the Z-scan technique. Hirshfeld surface analysis and fingerprint plots were utilized to gain insight into intermolecular interactions and atomic arrangements within the MQSSA crystal, emphasizing the roles of crystal structure in H...H and O...H/H...O interactions. Additionally, quantum computational methods were employed to evaluate various molecular-level electronic characteristics, including molecular orbitals, molecular electrostatic potential maps, and first and second-order nonlinear optical (NLO) polarizability, providing insights into the molecular-level NLO response properties.

Microplastic Analysis in Soil Using Ultra-High-Resolution UV–Vis–NIR Spectroscopy and Chemometric Modeling

The study of microplastics (MPs) in soils is impeded by similarities between plastic and non-plastic particles and the misidentification of MP by current analytical methods such as visual microscopic examination. Soil MPs pose serious ecological and public health risks because of their abundance, persistence, and ubiquity. Thus, reliable identification methods are badly needed for scientific study. One possible solution is UV–Vis–NIR spectroscopy, which has the ability to rapidly identify and quantify concentrations of soil microplastics. In this study, a full-range, field portable spectrometer (350–2500 nm) with ultra-high spectral resolution (1.5 nm, 3.0 nm, and 3.8 nm) identified three types of common plastics: low-density polyethylene (LDPE), polyvinyl chloride (PVC), and polypropylene (PP). Three sets of artificially MP-treated vermiculite soil samples were prepared for model prediction testing and validation: 150 samples for model calibration and 50 samples for model validation. A partial least square regression model using the spectral signatures for quantification of soil and MP mixtures was built with all three plastic polymers. Prediction R2 values of all three polymers showed promising results: polypropylene R2 = 0.943, polyvinyl chloride R2 = 0.983, and polyethylene R2 = 0.957. Our study supports previous work showing that combining ultra-high-resolution UV–Vis–NIR spectrometry with quantitative modeling can improve the accuracy and speed of MP identification and quantification in soil.