This study explains the intricate interplay between functional groups and the single crystal structure of the compound 1-(furan-2-yl)-3-(2,4,6-trimethoxyphenyl)prop-2-en-1-one (FT2MP) using Density Functional Theory (DFT) calculations. Notably, geometry optimization at B3LYP using 6-311G+(2d,p) closely aligned with experimental distances from X-ray diffraction (XRD) upon comparison. A Q-switched, frequency-doubled pulsed Nd. YAG laser (532 nm, 7 ns pulses), a 25 cm focal length lens, and a 0.001 mol/L FT2MP solution in Dimethylformamide was used to measure third-order nonlinear optical (NLO) parameters and subsequently the origin of second/third harmonic generation efficiency is discussed. The third-order nonlinear parameters of FT2MP were found to be Delta = 0.95, n(2) =-9.605 x 10 (9) cm(2)/W, beta = 2.74 x 10(-6) cm/W, and chi ((3)) = 5.58 x 10(-- 7) esu. Information about the electronic structure and reactivity of the molecule is provided via the addition of Global Chemical Reactivity Descriptors (GCRD), molecular electrostatic potential (MEP) and Frontier Molecular Orbitals (FMOs) for electronic structure and reactivity insights. Hirshfeld surface analysis was used to study intermolecular interactions. This investigation indicates the potential of FT2MP for third harmonic generation, providing a comprehensive understanding of its molecular structure, reactivity, and intermolecular interactions.

The functional moieties present in chalcone derivatives play a pivotal role in finely adjusting the thermal, optical, structural, and nonlinear optical (NLO) characteristics of the chalcone material. This paper details the synthesis of chalcone derivatives where three distinct trimethoxy substituents are integrated into the benzoyl moiety through carboxyl bonding with 2-acetyl pyridine. The synthesis employs the Schmidt condensation method, and the resultant samples are subject to scrutiny through FTIR and FT-Raman techniques to ascertain phase purity. The outcomes reveal substantial alterations in the structural, thermal, optical, and NLO attributes of the samples. The electron-donating property of the trimethoxy groups augments electron density within the chalcone molecule, thereby effecting multiple shifts in the material's characteristics. Interestingly, a methoxy group located at positions 2, 4, and 5 forms crystals with centrosymmetric properties. Conversely, relocating the methoxy groups to positions 3, 4, 5, and 2, 4, 6 induces a transformation from centrosymmetric to non-centrosymmetric crystal structures, resulting in a remarkable enhancement of NLO properties, encompassing second and third harmonic generation. Notably, the compound featuring trimethoxy substitution at positions 3, 4, and 5 demonstrates a 27-fold increase in second harmonic generation compared to the urea crystal. The detailed discussion encompasses the intricate relationship between the molecular structure and nonlinear properties, encompassing third harmonic generation.

Hydrogen gas, well-known for its remarkable energy density (0.0107 MJ/m3 at STP), is gaining recognition as a potential substitute fuel due to its positive environmental impact. However, the significant hurdle of secure and effective storage of H2 continues to be a pressing issue. Investigating this challenge, we delve into the potential of metal-organic frameworks (MOFs) as a compelling solution, subjecting them to a thorough analysis. We begin by underscoring the significance of H2 as an energy carrier, necessitating effective storage. We explore H2 adsorption on MOFs, highlighting their unique properties and potential for enhanced storage capacity. This review encompasses MOF structure, synthesis, and characterization techniques. It probes MOF-based on carboxylates, nanocomposites, and metal cluster-building components, emphasizing tunable properties and performance in H2 storage. Design strategies involving supramolecular Building Layers and MOF Pillaring Design are explored, showcasing their ability to enhance H2 adsorption properties. Additionally, we highlight fluorinecontaining and carbon-based MOFs, renowned for their remarkable H2 storage capabilities, achieved through tailored structures and expansive surface areas. This review explores the application of activated carbon derived from nanoporous polymers for hydrogen adsorption, emphasizing the crucial involvement of carbon-based materials in physisorption methods. To enhance the comprehension of MOFs, we integrate calculations using Density Functional Theory (DFT), Molecular Dynamics simulations, and Grand Canonical Monte Carlo (GCMC) simulations. This all-encompassing examination serves as a valuable reference for scientists and engineers, delivering profound insights and notable progress in the field of MOFs for hydrogen gas storage. Despite tremendous advancements in the field of MOF-based hydrogen storage, a significant gap remains for practical applications due to safety concerns. Further, storing H2 at 77 K is not very practical due to the requirement of liquid nitrogen. The preferred storage condition would be at 10-100 bar and near room temperature (298 K). Nevertheless, some outstanding results obtained with she-MOF-1 demonstrate exceptional H2 adsorption with a high storage capacity of 12.60 wt % at temperature 77 K and pressure 100 bars, making it promising for applications requiring substantial H2 storage. Additionally, MOF-5's remarkable BET (Brunauer-Emmett-Teller) surface area of 3512 m2/g positions it advantageously in adsorption-driven processes. Analysing H2 adsorption properties of fluorinated (Co -FINA -1 and Co -FINA -2) and non-fluorinated (Co-INA-1 and Co-INA-2) MOFs reveals that fluorination significantly increases H2 storage capacities, with Co -FINA -1 exhibiting the highest storage at 1.97 wt % at 77 K and 1 bar pressure, highlighting the positive impact of fluorination on H2 adsorption. The review highlights promising materials for hydrogen storage, such as she-MOF-1 with exceptional 12.60 wt % adsorption, MOF-5's remarkable BET surface area and the positive impact of fluorination on storage capacities, underscoring their potential for sustainable and economically viable H2 storage systems.

Photocatalytic hydrogen evolution has attracted tremendous interest as it offers a process for generation of green hydrogen based on solar radiation. But the process is extremely complex as many factors influence photocatalytic hydrogen evolution. While novel photocatalysts such as MOFs, perovskites, conjugated polymers, carbon-based materials, quantum dots, and others face challenges such as stability and scalability, semiconductor photocatalysts and cocatalysts such as TiO2/Pt, Ni–CdS, CdS/ZnO, CdS/ZnS have the advantages of simplicity in synthesis, stability, and scalability. Despite decades of research, challenges such as charge separation, spectrum usage, low hydrogen generation efficiency, photocatalyst stability and scalability persist. This review discusses what has been achieved so far in the domain of photocatalytic hydrogen evolution and presents a critical analysis of challenges to be addressed in developing a robust and practical photocatalytic hydrogen generation system based on efficiency of photocatalysts and their stability and the extreme importance of efficient reactor designs.

In this paper, V2O5 thin -films were deposited on glass substrates by using the ultrasonically nebulized spray pyrolysis technique. Doping concentration of 1 %, 2 %, and 7 % of Sn, in V2O5 thin -films is studied by using metal-semiconductor-metal (MSM) based device structure. X-ray diffractometer (XRD) and field emission scanning electron microscope (FESEM) were used to analyze the surface morphology of the thin films. The XRD spectroscopic analysis shows the crystal size of above -mentioned samples, to be respectively 39 nm, 58 nm, 60 nm and 72 nm. The FESEM images showed the enhancement of crystal size with increase in Sn doping concentration. The optical properties of Sn doping on V2O5 thin film were studied by using UV-Vis spectrometer. The UV-Vis spectroscopic analysis shows that the absorption coefficient values decrease with increase in concentration of Sn metal doping in V2O5 thin film. The activation energies of all thin-film samples were calculated from Arrhenius plots and were found to be 0.938 eV, 1.101 eV, 1.11 eV and 1.169 eV, respectively, for all the thin-film samples mentioned above. The MSM based structure was fabricated by using a shadow mask and thermal evaporation. Later, the I -V characteristics of all the thin films were obtained by using semiconductor parameter analyzed at a biased voltage between -50 V and + 50 V with a step size of 1 V. Rectification ratio of the V2O5 films is significantly enhanced as the doping concentration increases. It was found that the rectification ratio of undoped V2O5 thin films increased linearly from 1.018 to 1.059 with an increase in temperature from room temperature to 130 degrees C. Similar trend was followed for 1 % (from 1.079 to 1.198), 2 % (from 1.081 to 1.224) and 7 % (from 1.095 to 1.311) Sn doped films. These results show the potential application of V2O5 thin films in the field of optoelectronics and thin film gas sensors.

One of the most important features of polymer electrolyte membrane (PEM) fuel cells is durability. Improving fuel cell life and membrane electrode assemblies (MEA) durability translates to significant cost savings for fuel cells. This review is about the study of the degradation mechanisms of PEM fuel cells. The Degradation mechanisms include chemical, mechanical, catalyst, and thermal degradation. The reason for degradation also may be due to the presence or formation of contaminants during dynamic conditions. From the review, it has been observed that Pt catalysts made of Pt or Pt-alloy catalyst value superior to those required for complete Pt oxide.

Glass and fused-quartz are commonly used in microfluidic and optical sensor devices due to their chemical inertness and optical transparency. This study focuses on the etching of glass and fused-quartz using chemical etching and electrochemical discharge machining (ECDM) techniques. The aim is to compare their effectiveness and identify the most suitable technique for micro-channel formation. Chemical etching with hydrofluoric acid /Buffered hydrofluoric acid solution is commonly used for deep etching in silicon dioxide, but becomes challenging for long etching periods beyond 100 µm depth. There are primarily two problems: a) the integrity of the mask used for defining micro-channels; b) undercut below the mask edges. These two problems seriously limit the chemical etching process beyond 100 µm depth. A mask made of evaporated Au/Cr has been found effective in protecting borosilicate-glass during etching to a depth of 148 µm. However, etching of fused-quartz is much slower than borosilicate-glass while the mask integrity remains the same. Hence obtaining micro-channels beyond 100 µm depth is extremely challenging in fused-quartz. This study compares our results of chemical etching and ECDM of fused-quartz, concluding that electrochemical discharge machining is the effective and reliable technique for micro-channel formation on fused-quartz. The results showed a significant enhancement in surface quality as proven by UV–vis transmission data obtained after well-optimized BHF treatment on ECDM samples. Specifically, this treatment involved subjecting ECDM etched fused-quartz samples to a 1:1 BHF treatment for duration of 5 min. Following this optimal BHF treatment, the UV–vis transmission data showed an increase from 36% to 44% thereby meaning the surface roughness caused by ECDM has been smoothened during 5 min 1:1 BHF treatment. These findings provide valuable insights into the etching processes, masking materials, and techniques for micro-channel fabrication, with potential applications in microfluidics and optical sensing devices.

The structural, optical, photoluminescence and electrical behaviour of aluminium and indium doped ZnO (AIZO) thin films are investigated for different dopant compositions. AIZO thin films were grown on glass substrates using an ultrasonic nebuliser spray pyrolysis process at 400 degrees C substrate temperature. Ammonium acetate is used as a stabiliser as well as a binding agent in the precursor solution. It was found that a shift in crystalline nature as the deposition time increases. Further, these thin films show hexagonal nanostructures, according to XRD investigations. Optical studies show that AIZO films have transmittance of more than 70%. Electrical study reveals that resistivity of AIZO thin films range from 2.35 to 4.591 x 10(-3) Omega cm. Copyright (C) 2022 Elsevier Ltd. All rights reserved.

The removal of material, selectively or non-selectively, from the surface of glasses by using acidic, caustic, or abrasive chemicals is referred to as glass etching. Wet and dry etchings are extensively used for variety of applications, including flow channel designs in fuel cell electrodes. Since precise micro-level etching is challenging, optimization of the etching parameters is important. This paper reviews wet etching of glasses including fused quartz for formation of microchannels and microstructures for a variety of applications. The review also discusses different etch mechanisms including etch parameters and surface microstructure of the etched glass. It is found that HF concentration and etching time play a major role on the resulting surface microstructure of glass materials. The paper also describes the use of HF buffered with NH4F solutions to improve the quality of the etched surface.

Human breath analysis provides a non-invasive and fast method for identifying numerous volatile organic compounds that are disease markers. Breath analysis on a small device that is connected to the Internet of Things and uses chemi-resistive semiconductor with extremely low energy usage will build new roads for detection of diseases and monitoring patients. Nano-structures of various forms, synthesized by diverse nano-meter-scale synthesis methods, can be utilized to achieve this aim. Metal oxide nano-structures allow a well-built gas-sensing layer interaction and, as a result, show a higher sensitivity than traditional materials due to features such as high surface-to-volume ratios and, consequently a large number of surface sites exposed to gas. This paper provides an overview of advances in chemi-resistive nano-structures as gas sensing materials for exhaled breath detection, with the goal of assisting patients with various conditions in their disease screening. The many types of chemi-resistive materials utilized in breath sensors have been discussed, as well as their limits and future prospects also presented.

A novel glutaraldehyde cross-linked Chitosan-PVA (GCP) polymer composite membrane is used to create a water filtration device. The GCP polymer membrane is synthesised using the solution casting process. GCP membranes are characterised using different techniques. The results showed that this filtration unit developed using GCP membrane is effective in reducing the Lead, Cadmium, Sodium and Iron content by 99.32%, 98.1, 88.21% and 78.9% respectively. The creation of nano-pores in GCP membrane, the adsorbent property of GCP and the thermal and chemical stability of GCP are the key factors leading to high performance filtration of major metal contaminants in ground water.

ZnO thin films doped with Indium were produced on glass substrates by the process of spray pyrolysis. XRD results showed a polycrystalline hexagonal wurtzite structure. The structural, PL and optical characteristics of IZO thin films were investigated with increasing doping concentration. X ray diffraction studies with increasing Indium doping concentration show a change in the preferential orientation from 0 0 2 to 1 0 1 crystal planes. UV-vis-NIR spetra was collected and the results show that the band gap of the IZO thin film was found to be 3.5 eV. The optical transmittance spectra for thin films coated with 3 at% Indium concentration revealed high transmittance of 80-90% in the visible region. Other than the characteristic blue-green emission in In-doped thin films three more PL emissions were observed. Copyright (C) 2022 Elsevier Ltd. All rights reserved.

The design of a piezoelectric PZT/P(VDF-TrFE) based Microelectromechanical system cantilever beams for a very low frequency applications, using silicon bulk-micromachining technology is described in this paper. The natural frequencies of cantilever beams were calculated using the COMSOL software. For signal output, the cantilever-beam structure contains a layer of PZT/P(VDF-TrFE) as well as chrome-gold interdigitated electrodes. According to the simulation results, the cantilever-beam with dimensions of 10mmx3mmx5 mu m has a lowest resonant frequency of 95.56 Hz, implying that PZT/P(VDF-TrFE) is an appropriate piezoelectric material for really low frequency uses such as building and structure health monitoring. Copyright (C) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of 2022 International Conference on Recent Advances in Engineering Materials.

Using the ultrasonically nebulized spray pyrolysis of the aqueous combustion mixture (UNSPACM) technique, the effect of precursor dilution solvents on the growth of V2O5 thin films is reported. V2O5 thin films are grown by spraying an aqueous combustion mixture (ACM) onto glass substrates at 400°C. Methanol and ethanol are used to dilute the ACM. FESEM, XRD, and FT-Raman spectroscopic analysis are used to examine the surface microstructure, crystallographic information, and functional groups of the grown thin films respectively. The results show that thin films grown by diluting ACM with methanol produce the best results.

Precursor stabilized Gallium doped ZnO thin films were grown using spray pyrolysis on glass substrates. UV-vis spectrophotometry and an X-ray diffractometer were used to characterise the GZO thin films. Gallium is doped with a concentration ranging from 1 at% to 4 at% and its effects on structural and optical features were studied. XRD studies found the thin films to be polycrystalline with a hexagonal wurtzite structure. In the visible range of wavelength (400-800 nm), all GZO films exhibit average transmittance above 90%, with a pronounced absorption edge in the UV area. The PL emission spectra show the Near band-edge emissions at about 389 nm and strong deep-level emissions from oxygen defect states at about 545 nm are observed in all the films. With increase in concentration of Ga, the intensity of these two bands decreased. Copyright (C) 2022 Elsevier Ltd. All rights reserved.

Breath sensors have the potential to transform medical diagnostics by providing non-invasive and customised on-demand detection and monitoring of health indicators. The nanostructured film's gas sensing capacity is impressive in terms of response time, detection limit, & reversibility. In this work, we present advances in the detection of trace level ammonia vapor in breath, a bio-marker for renal disorders, using extremely selective, sensitive, and stable sensors at sub-ppm levels. This painless, efficient method will enhance the existing gold standard for detecting renal disease, allowing for speedy and early identification. At the end, we present an outlook for the upcoming development of efficient ammonia sensors.

Hydrogen fuel cells have been designed and fabricated with an aim to investigate effect of cell clamping pressure and hydrogen flowrates on the performance of fuel cells. Fuel cells with active area 1.9 cm x 1.6 cm were fabricated with aluminum anode, cathode and other accessories. Membrane Electrode Assembly (MEA) was made up of nafion 212 (50 mu m) membrane sandwiched between two gas diffusion electrodes (GDE) on either side of nation membrane. Anode and cathode GDE had carbon cloth with 0.25 mg/cm(2) and 0.50 mg/cm(2) Pt loading, respectively. Double serpentine flow channels were used for the flow of hydrogen and oxygen at anode and cathode. Hydrogen was humidified with an external humidifier. Cells were fabricated with two clamping pressures, 5 kg/cm(2) and 25 kg/cm(2) both at 80 degrees C. Hydrogen and oxygen flowrates were varied from 10 sccm to 70 sccm. The polarization plots indicate that the cell with clamping pressure of 25 kg/cm(2) and with a flowrate 20 sccm have higher power output (350 mW/cm(2)) compared to other flowrates thereby implying an optimum flowrate for a given design. (C) 2019 Elsevier Ltd. All rights reserved.

Organic materials with good third-order nonlinear optical (NLO) properties are used in optoelectronics for protecting human eyes and sensors from high intensity laser light. In this regard, herein we report the synthesis, structural analysis, and third-order NLO properties of an organic molecule N'-[(E)-(4-fluorophenyl)methylidene]biphenyl-4-carbohydrazide (FMBC) containing hydrazone moiety. The formation of the synthesized molecule is confirmed by identifying the functional groups through FTIR spectral analysis. The material possesses good thermal stability before the melting point of 242.5 degrees C and transparent in the entire visible region of the EM spectrum. The photoluminescence study revealed the blue light-emitting property of FMBC. The crystal structure is stabilized by N-H center dot center dot center dot O, C-H center dot center dot center dot O, and C-H center dot center dot center dot F hydrogen bond interactions. The interconnects in the crystal packing were envisioned quantitatively using Hirshfeld surfaces (HS) by 2D fingerprint plots. The main contribution to the HS comes mainly from C-H, H-H, and O-H interconnects which cover about 80 % of the total HS surface. The enrichment ratios show that the favorable contacts accountable for the crystal packing are C center dot center dot center dot H, N center dot center dot center dot H, O center dot center dot center dot H, and F center dot center dot center dot H. The breakdown of the interaction energies obtained for various molecular pairs shows the nature and strength of the interactions. The calculation of 3D energy frameworks suggests that contacts formed in the structure are largely due to the dispersion force followed by the electrostatic potential. Third-order NLO coefficients were extracted under the continuous wave (CW) regime using z-scan technique. The material is an excellent optical limiter with a threshold value of 3.42 kJ/cm(2). (C) 2021 Elsevier B.V. All rights reserved.

The work presented here describes a structural design of piezoelectric co-polymer P(VDF-TrFE) cantilever-beams for very low frequency applications; the design is based on silicon bulk-micromachining and micro-electromechanical systems technology. COMSOL simulation software has been used to study the mechanical and electrical behavior of cantilever-beams. The dimensions of the beams designed are: 3mm x 0.6mm x 5 mu m, 5mm x 1 mm x 5 mu m. and 10mm x 3mm x 5 mu m. The configuration of the cantilever-beam comprises of an active layer of piezoelectric P(VDF-TrFE) with chromegold interdigitated electrodes for electrical signal output generated due to vibration of piezoelectric beams. Simulation results show that the cantilever-beam of dimension 10mm x 3mm x 5 mu m has a resonant frequency of 42.68 Hz, indicating that P(VDF-TrFE) is a favorable piezoelectric material for low and very low frequency applications. (C) 2019 Elsevier Ltd. All rights reserved.

The novel Schiff base hydrazones have exciting biological and nonlinear optical (NLO) applications. In our present work, a novel Schiff base hydrazone compound: N '-[(E)-(2,5-dimethoxyphenyl) methylidene] biphenyl-4-carbohydrazide(DMBC) was synthesized and subjected to FTIR characterization. Quantum chemical calculations were used to further interpret the observed FTIR spectrum quantitatively using potential energy distribution (PED). The geometry of DMBC was optimized using the density functional theory (DFT) approach with the help of the Gaussian 09 W package. Molecular electrostatic potential (MEP) surface and HOMO-LUMO studies were used for the understanding of chemical reactivity sites and the calculation of global reactivity parameters. Intra- and intermolecular interactions within the molecule and crystal packing respectively were examined by NBO and Hirschfeld surface analysis. Nonlinear optical response, which depends upon the delocalization of the pi-electrons and intramolecular charge transfer (ICT), was evaluated by dipole moment mu, the polarizability alpha, and first-order hyperpolarizability beta calculations. Hyper polarizability of DMBC molecule is calculated to be 8.0280253 x 10(-30) esu which is 21 times greater than the value of urea. Therefore, synthesized DMBC molecule showed the potential for its use in NLO applications.