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Excessive Cu2+ intake can cause neurological disorders (e.g. Wilson's disease) and adversely affect the gastrointestinal, liver, and kidney organs. The presence of Cu2+ is strongly linked to the emergence and progression of Wilson's disease (WD), and accurately measuring the amount of copper is a crucial step in diagnosing WD at an early stage in a clinical setting. In this work, CQDs were fabricated through a facile technique as a novel fluorescence-based sensing platform for detecting Cu(II) in aqueous solutions, and in the serum samples of healthy and affected individuals by WD. The CQDs interact with Cu(II) ions to produce Turn-on and Turn-off states at nano-molar and micro-molar levels, respectively, with LODs of 0.001 µM and 1 µM. In fact, the Cu2+ ions can act like a bridge between two CQDs by which the charge and electron transfer between the CQDs may increase, possibly can have significant effects on the spectroscopic features of the CQDs. To the best of our knowledge, this is the first reported research that can detect Cu(II) at low levels using two different complexation states, with promising results in testing serum. The potential of the sensor to detect Cu(II) was tested on serum samples from healthy and affected individuals by WD, and compared to results obtained by ICP-OES. Astonishingly, the results showed an excellent correlation between the measured Cu(II) levels using the proposed technique and ICP-OES, indicating the high potential of the fluorimetric CQD-based probe for Cu(II) detection. The accuracy, sensitivity, selectivity, high precision, accuracy, and applicability of the probe toward Cu(II) ions make it a potential diagnostic tool for Wilson's disease in a clinical setting. [ABSTRACT FROM AUTHOR]

In exploring nature's potential in addressing diabetes-related conditions, this study investigates the therapeutic capabilities of 3-formyl chromone derivatives. Utilizing in silico methodologies, we focus on 6-substituted 3-formyl chromone derivatives (1–16) to assess their therapeutic potential in treating diabetes. The research examined the formyl group at the chromone's C-3 position. ADMET, biological activities, were conducted along with B3LYP calculations using 3 different basis sets. The analogues were analyzed based on their parent structure obtained from PubChem. The HOMO–LUMO gap confirmed the bioactive nature of the derivatives, NBO analysis was performed to understand the charge transfer. PASS prediction revealed that 3-formyl chromone derivatives are potent aldehyde oxidase inhibitors, insulin inhibitors, HIF1A expression inhibitors, and histidine kinase. Molecular docking studies indicated that the compounds had a strong binding affinity with proteins, including CAD, BHK, IDE, HIF-α, p53, COX, and Mpro of SARS-CoV2. 6-isopropyl-3-formyl chromone (4) displayed the highest affinity for IDE, with a binding energy of − 8.5 kcal mol−1. This result outperformed the affinity of the reference standard dapagliflozin (− 7.9 kcal mol−1) as well as two other compounds that target human IDE, namely vitexin (− 8.3 kcal mol−1) and myricetin (− 8.4 kcal mol−1). MD simulations were revealed RMSD value between 0.2 and 0.5 nm, indicating the strength of the protein–ligand complex at the active site. [ABSTRACT FROM AUTHOR]

Context: In the present work, the influence of aromatic ring substitution on a series of small-donor organic molecules (A, B, C, D, and E) with isoxazole cores was investigated for photovoltaic applications in organic solar cells. Frontier molecular orbital analysis, chemical reactivity descriptors, dipole moment, and population analysis showed that all the organic materials have intramolecular charge transfer abilities capable of donating electrons to the acceptor material (PCBM). The required photovoltaic parameters such as Voc, FF, Jsc, LHE, and other associated optoelectronic parameters are reported. The results demonstrate that aromatic ring substitution influences charge transfer and power conversion efficiencies of solar cells. That is, an increase in the aromatic character of a material increases its charge transfer, and as a result, its photovoltaic properties are increased. Additionally, all the investigated derivatives are good charge transporters with suitable electron reorganization energies, which are beneficial for minimizing energy loss. Hence, these organic derivatives with isoxazole backbones are promising materials and may provide fresh insights into the design of new materials for organic solar cell applications. Method: All calculations were performed using DFT and the ORCA 4.1.0 program package as the main tool for geometry optimization and frequency calculations. The Avogadro 1.2.1 visualization tool was used to prepare all input files executed by ORCA 4.1.0. The BP86, B3LYP, and wB97M series of functionals coupled with the def2/TZVP basis set were employed for geometry optimization. All energy-related calculations were carried out using the M06-2x functional. Multiwfn version 3.7 was used for aromaticity and population analysis. Excited state and UV-visible spectra were simulated using the TD-DFT method at the CAM-B3LYP-D3, wB97X-D3, and PBE0-D3 coupled with the ma-def2-TZVP basis set. Moreover, solvent effects were incorporated using the SMD scheme as incorporated in the ORCA software. Lastly, the RIJCOSX approximations were used to speed up calculations while maintaining accuracy. [ABSTRACT FROM AUTHOR]

A nanocomposite of Ce-doped ZnO/r-GO was synthesized using a conventional hydrothermal method. The synthesized nanocomposites were utilized for the purpose of sensitive and selective detection of cyclobenzaprine hydrochloride (CBP). The properties of the composite were extensively analyzed, including its morphology, structure, and electrochemical behavior. This study investigates the application of a modified glassy carbon electrode for the detection of CBP, a muscle relaxant used to treat musculoskeletal diseases that cause muscle spasms. The electrode is modified with Ce-doped ZnO/r-GO. Various detection methods, such as cyclic voltammetric and square wave techniques (SWV), were utilized. The composite material showed high effectiveness as an electron transfer mediator in the oxidation of CBP. The electrode showed a good response for SWV evaluations in CBP identification, with a minimum detection limit of 1.6 × 10−8 M and a wide linear range from 10 × 10−6 M to 0.6 × 10−7 M, under ideal conditions. The rate constant for charge transfer (ks) and the estimation of the electrochemical active surface area were obtained. A developed sensor exhibited desirable selectivity, long-lasting stability, and remarkable reproducibility. A sensor was used to analyze water, human serum, and urine samples, resulting in positive recovery results. [ABSTRACT FROM AUTHOR]

Binary antimonene-phosphorene, a novel 2D semiconductor material, shows potential applications in gas sensing due to its favorable properties. In this work, the sensing properties of binary antimonene-phosphorene nanoribbons by varying the phosphorus mole fraction for the adsorption of NO, CO, NO2, CO2, SO2, SO3, H2S, NH3, O2, and N2 gas molecules are theoretically investigated with first-principles method based on the density function theory. The adsorption distance, adsorption energy, charge transfer, work function, and recovery time of gas molecules adsorbed on the different substrates of phosphorus mole fraction are calculated and compared to evaluate the sensing performance of these structures. The results demonstrate that all the examined gas molecules form stable physisorption with binary nanoribbons (except O2 molecule). Through the analysis of adsorption energy and charge transfer, it can be seen that binary nanoribbons with mole fractions of 25 and 75% have higher selectivity and sensitivity to gas molecules. For example, the charge transfer results show that there is more charge transfer from SO3 (0.456 e) and O2 (0.4 e) gas molecules to 25 and 75% phosphorus substrates than other substrates of mole fraction, respectively. Moreover, for a better comparison, the I–V characteristics of different phosphorus mole fraction are calculated for SO3 and O2 gases. The calculated current–voltage curves confirm the charge transfer results. As a result, our theoretical studies show that binary nanoribbons with some mole fractions can offer promising platform for gas sensing applications. [ABSTRACT FROM AUTHOR]

A novel cyclic chalcone fluorescent probe C-PN was synthesized to detect ONOO−. After reaction with peroxynitrite, the double bond of C-PN in the cyclic chalcone structure was disconnected, which caused the change of intramolecular charge transfer (ICT) effect, emitting blue fluorescence and quenching orange red fluorescence. Visible to the naked eye, the color of the probe solution changed. The probe showed low sensitivity (detection limit = 20.2 nm), short response time (less than 60 s) at low concentration of ONOO−, good visibility, and good selectivity and stability for ONOO−. [ABSTRACT FROM AUTHOR]

Novel alginate-based binders containing either catechol (d-Alg) or sulfonate (s-Alg) functional groups were developed and characterized to improve the capacity decay performance and better stability of Li-ion batteries. The electrochemical performance of silicon–graphite (Si/Gr) anode with alginate-based binders were compared to the commonly used CMC/SBR binder. The active material in the anodes was the ball-milled Si/Gr (20:80 wt%) powder mixture. A comprehensive electrochemical study was carried out through rate capability test, cycle test, differential capacity analysis (dQ/dV), and electrochemical impedance spectroscopy (EIS). The functionalized s-Alg binder showed the lowest electrolyte uptake (11.5%) and the highest tensile strength (97 MPa). Anodes with s-Alg exhibited high initial capacity (1250 mAh g−1) and improved decay performance (580 mAh g−1 at 0.2 C), by ~ 65% higher compared to CMC/SBR binder. The influence of pH value of s-Alg binder preparation showed that anodes prepared at pH 3 of s-Alg exhibit better performance, reaching 800 and 750 mAh g−1 at 0.1 and 0.2 C, respectively, due to the stronger bonding formation and compactness of anode layer which providing low charge transfer and solid electrolyte interface resistance. [ABSTRACT FROM AUTHOR]

Exploring inorganic flower-like nanosheets is of increasing interest not only for fundamental research, but also for development of devices due to their good chemical stability, versatility, and high surface-to-volume ratio. In this work, flower-like TiO2 nanosheets (FTN) are successfully synthesized by a facile hydrothermal method. Notably, a series of single-factor experiments are carried out to drive multiple functional components in order to integrate into a single flower-like nanostructure perfectly. In addition, these experimental results further reveal that alcohol/glycerol molar ratio acts in a vital role for preparing optimal flower-like morphology and structure of TiO2. Furthermore, the photodegradation pathways and mechanism of Levofloxacin (LVOF) by FTN are shown according to photodegradation intermediates of LVOF, trapping experiments, and ligand-to-metal charge transfer (LMCT) sensitizing effect. Therefore, the present work not only demonstrates the controlled synthesis of flower-like TiO2 nanosheets, but also provides a guide for constructing other inorganic flower-like nanosheets or TiO2-based photocatalysts with optimal morphology, structure and photocatalytic performance. [ABSTRACT FROM AUTHOR]

The current work assessed the corrosion inhibitory efficacy of three ligands, namely methyl 2-((2-hydroxynaphthalen-1-yl)diazenyl)benzoate(MDN), 1-((3,4-dimethylphenyl)diazenyl)naphthalen-2-ol (DDN), and 3-((2-hydroxynaphthalen-1-yl)diazenyl)benzonitrile (HDN). Electrochemical and quantum methodologies, along with UV–Vis, SEM, and EDX, were employed. The anticorrosion process was comprehensively investigated. Potentiodynamic polarization validated the mixed type nature of inhibitors by demonstrating a drop in the cathodic hydrogen evolution reaction and the anodic metal dissolution, resulting to a significant decrease in corrosion current densities. Enhanced rates of effectiveness are achieved with higher inhibitor doses. Electrochemical impedance spectroscopy investigations confirmed the formation of a protective layer at the metal/solution interface, demonstrating that charge transfer was the primary cause of mild steel corrosion. The inhibitory potencies of the studied inhibitors at 10−3 M were 94.65, 94.56, and 93.63% for MDN, DDN, and HDN, respectively. The presence of several attributes in the molecular skeleton, such as nitrogen heteroatoms, aromatic rings, and the ester substituent group (CO2CH3), enhanced the availability of non-bonded and π-electrons and created stable covalent bonds by donating electrons to the iron surface. The inhibitory efficiency was better than 89% across all temperature ranges, suggesting the potential benefits of inhibitors at elevated temperatures. Adsorption trials revealed high effectiveness in corrosion control on mild steel, with Langmuir-based physisorption and chemisorption. The impact of electronegative O and N atoms, along with aromatic rings, in forming protective coatings was demonstrated by quantum chemistry computations which linked molecular structure and charge density patterns to the inhibition potency of MDN, DDN, and HDN, highlighting MDN's strong adsorption capacity. [ABSTRACT FROM AUTHOR]

Hole transport materials (HTMs) are indispensable for achieving high-performance perovskite optoelectronic devices. We have designed hole transport layer materials, and the geometries, electronic properties, excited state properties, and carrier mobilities of the promising experimental HTM molecule PCA-2 and designed molecules based on PCA-2 by substituting the core structures (named DMS, DMC, DMN and DMO) have been theoretically investigated by employing quantum chemistry methods. Our results show that all the HTMs exhibit excellent planarity and light absorption properties, which are beneficial for facilitating intramolecular charge transfer and enhancing device short-circuit current. The stability of all the studied HTMs was better than that of Spiro-OMeTAD. Additionally, the designed molecules exhibit good capability of hole injection, with DMC, DMN and DMO also displaying effective electron-blocking ability. The solubility of DMN surpasses that of all other molecules. Among the designed HTMs, the hole mobilities of all HTMs except for DMC, are improved compared with the experimental molecule PCA-2. Notably, DMN not only exhibits energy levels matching with perovskite but also has the largest hole mobility, which gives it the potential to be an ideal HTM. This comprehensive study will provide insights into charge transport materials for perovskite optoelectronic devices. [ABSTRACT FROM AUTHOR]

Single-atom photocatalysts exhibit outstanding performance in energy and environmental photocatalysis, due to their exceptional capabilities in enhancing light-harvesting, charge transfer dynamics, and surface reactions. The key to preparing single-atom photocatalysts lies in developing an appropriate metal-support that can prevent aggregation or sintering during synthetic procedures. In this work, a Co(II)-urea complexe in-situ formed in melamine was employed as single-atom Co precursors to synthesize an efficient single-atom Co decorated P doped g-C3N4 (Co/PCN) photocatalyst. The high-angle annular dark field transmission electron microscope (HAADF-TEM) results indicated abundant Co single atoms were immobilized in the g-C3N4 matrix. Under visible-light irradiation, the as-prepared photocatalysts show remarkably enhanced photocatalytic performance. Especially, loaded with 1.5 wt% single atoms Co, the optimized Co/PCN exhibits H2 evolution of 892.5 µmol g−1 h−1, which is 33 times higher than that of PCN, and even twice as much as that of Pt-loaded g-C3N4 (Pt/PCN). The enhanced photocatalytic activity is ascribed to the synergistic effect between single-atom Co and P doping, which facilitates efficient light harvesting, charge separation, and migration. It is believed that this study paves a new avenue for developing high-efficiency single-atom photocatalysts. [ABSTRACT FROM AUTHOR]

A novel 2,4-dibromo-6-(1H-phenanthro[9,10-d]imidazol-2-yl)phenol crystal has been reported and characterized by FT-IR, 1H NMR, 13C NMR. Single crystal XRD studies reveals that the compound crystalizes into triclinic crystal system with P-1 space group, and crystallographic data has been deposited in the Cambridge crystallographic data center with CCDC Number: 2246180. Various computational analysis like, Hydrogen bond analysis, Molecular electrostatic potential analysis, Natural population analysis, hirshfeld surface, and Frontier molecular orbital analysis were performed to elucidate the structure of the crystal. Marcus-Hus semiclassical model for charge transfer in organic materials is applied for the calculation of charge transfer rate. The calculation of reorganization energy and coupling constant reveals that the compound could be investigated as hole transport material. Synthesis, characterization, and computational analysis of Imidazole-based Organic crystals as charge transport material. [ABSTRACT FROM AUTHOR]

Concept drift is one of the most prominent issues in streaming data that machine learning models need to address. Most of the research in the field of concept drift targets updating the prediction model for recovery from concept drift. A little effort has been put into the development of a learning system that can learn drifting concepts with minimal overhead. In this paper, a dynamic ensemble classifier is designed to detect and adapt the concept drifts in streaming data. Thereupon, a novel approach- Selective Ensemble using Transfer Learning (SETL) is proposed that has the ability to adapt the new concept of data. It employs a transfer learning and a weighted majority voting scheme to enable resource optimization. It also overcomes the issues, such as negative transfer and overfitting that may occur during the process of transfer learning. The experiments are performed using real-world open-source datasets. The results indicate that SETL outperforms existing state-of-the-art algorithms for most of the datasets in terms of performance metrics such as Accuracy, F1-score, Kappa measure, precision and recall. [ABSTRACT FROM AUTHOR]

Extensive investigations have been carried out on spinel mixed transition metal oxide-based materials for high-performance electrochemical energy storage applications. In this study, mesoporous Mn-substituted MnxZn1−xCo2O4 (ZMC) ternary oxide microspheres (x = 0, 0.3, 0.5, 0.7, and 1) were fabricated as electrode materials for supercapacitors through a facile coprecipitation method. Electron microscopy analysis revealed the formation of microspheres comprising interconnected aggregates of nanoparticles. Furthermore, the substitution of Mn into ZnCo2O4 significantly improved the surface area of the synthesized samples. The electrochemical test results demonstrate that the ZMC3 oxide microspheres with an optimal Mn substitution exhibited enhanced performance, displaying the largest specific capacitance of 589.9 F g−1 at 1 A g−1. Additionally, the ZMC3 electrode maintained a capacitance retention of 92.1% after 1000 cycles and exhibited a significant rate capability at a current density of 10 A g−1. This improved performance can be ascribed to the synergistic effects of multiple metals resulting from Mn substitution, along with an increase in the surface area, which tailors the redox behavior of ZnCo2O4 (ZC) and facilitates charge transfer. These findings indicate that the incorporation of Mn into mixed transition metal oxides holds promise as an effective strategy for designing high-performance electrodes for energy storage applications. [ABSTRACT FROM AUTHOR]

To investigate the effects of polymer donors with isomeric alkyl chains on the interfacial charge-transfer (CT) processes, the rates of exciton dissociation (kED) and charge recombination (kCR) have been calculated for complexes PM6/Y6 and PM6i/Y6, where isomer PM6i was designed by shifting the side chains in the electron-withdrawing units to the thiophene-bridges based on PM6. For complex PM6/Y6, kED of PM6 and Y6 exciton are calculated to be 1010–1012 s−1 and 1012–1013 s−1, and kCR is 1011–1012 s−1 for recombination of the lowest CT (CT0) excitons into the lowest triplet states of Y6, which are consistent with the experimental results. When going to complex PM6i/Y6, kED of PM6i exciton is higher than that of PM6 exciton, and of Y6 exciton is decreased to 1011–1012 s−1, but kCR is decreased to 1010–1011 s−1. The calculated results reveal that isomeric alkyl chains of polymer donors can enhance the polymer exciton dissociation and suppress the charge-recombination processes, underlining the important role of isomeric alkyl chains in design of polymer donors for high performance non-fullerene organic photovoltaics. [ABSTRACT FROM AUTHOR]

The influence of certain thiadiazole derivatives on the corrosion of Muntz metal (60Cu–40Zn) in sulfide-polluted artificial seawater was analyzed using electrochemical and physiochemical studies methods. The surface morphology was examined by SEM to determine this inhibition mechanism. Elemental composition of the corroded alloy specimens was investigated in the presence and absence of thiadiazole derivatives using energy-dispersive X-ray analysis (EDX). Thiadiazole derivatives were found to successfully suppress Muntz metal corrosion. Adopting the weight loss method, the optimum concentration of inhibiting thiadiazole derivatives was 2.32 mM owing to the thiadiazole surface coverage and adsorption with increasing concentration. Among the derivatives investigated, N-(5-(4-aminophenyl)-1,3,4-thiadiazole-2-yl)-2-diphenylamino) acetamide (ATPA) showed the highest corrosion protection efficiency. EIS studies showed that charge transfer resistance occurs because of the presence of an inhibitor. Moreover, increasing thiadiazole concentration decreased the double-layer capacitance (Cdl) value because less charged species were attracted to the metal surface. Potentiostatic current–time transient techniques showed that ATPA hindered the corrosion rate owing to the substituted thiadiazoles. Polarization measurements clearly showed that the inhibitors suppressed both anodic and cathodic reactions. Consequently, accelerated leaching studies showed concentrations of Zn and Cu released from the alloy reducing as concentrations of inhibitors increased, in addition to the corrosion protection efficiency (%) increasing. The highest value was obtained at 2.32 mM of inhibitor. In conclusion, this study demonstrates that these compounds inhibit corrosion via chemisorption of organic compounds. Among these compounds, ATPA was found to offer better corrosion inhibition than others. [ABSTRACT FROM AUTHOR]

The extensive application of SERS requires a reduction in complexity and difficulty in substrate preparation. Here, the study proposes a simple yet effective technique for the synthesis of few-layered MoS2–WS2 composite structures and highlights the potential of these nano-composites as low-cost SERS substrates. A highly fluorescent dye, Rhodamine 6G (R6G) has been employed as a probe. A better enhancement ability was observed for the MoS2–WS2 nano-composite structures and a series of R6G signature peaks can be detected even down to 10–7 M concentration. The presence of surface roughness due to the formation of multiple inter- and intra-flake heterojunctions may provide a larger contact area between the substrate and the probe. Hence, the improved enhancement is probably due to the higher adsorption of the R6G molecules on the nano-composites and the effective charge transfer between them. Additionally, the detection ability of the MoS2–WS2 composite structures was sustained over a long period after storing the same at room temperature. The study provides a new incentive for metal-free low-cost SERS sensing by engaging 2D materials. [ABSTRACT FROM AUTHOR]

Anthracene molecule possesses remarkable optical activity and till today this molecule is of special interest of scientists. Present study is focused on the study of effects of Chloride, Sulfate, Nitrate and Ferrate salts on absorption and emission spectra of targeted fluorophore in carbontetrachloride, chloroform, dichloromethane and methanol. Prominent solvatochromic effects shows dependence of HOMO–LUMO orbitals on solvent polarity. Anthracene molecules exhibits changes in absorption and emission spectra, and show both ON and ON–OFF behavior on addition of said ions. Based on experimental results it was concluded that fluorophore molecule could be used more effectively as UV–Visible (UV-V) sensors in comparison to the emission sensor. [ABSTRACT FROM AUTHOR]

Simple hydrothermal method can be applied for synthesizing rod shape Gd2O3:Eu3+ phosphors. X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy are used for the characterizations of samples. Increase of Eu3+ concentration in Gd2O3:Eu3+ can cause red shift in the charge transfer band (CTB) of Eu – O. The nature of Eu3+ surroundings is asymmetric. It is ascertained from PL emission studies. The calculation of second order crystal field parameter from PL spectra corroborates the asymmetric environment of Eu3+. PL emission and decay lifetime studies confirm the existence of quenching due cross-relaxation. The quantum yield for Y2O3:Eu3+ (19 at.%) under 265 nm excitation is found to be 7%. [ABSTRACT FROM AUTHOR]

Herein, α-cyanostilbene-based luminogen with an electron donor-π-electron acceptor (D-π-A) architecture was formylated into the salicylaldehyde-analogue luminogen, followed by the Schiff base reaction with phenylamine, a red-emitting luminogen was elaborately designed and successfully synthesized in a high yield of 89%. Its well-defined structure was confirmed by FT-IR, MALDI-TOF-MS, HR-MS and 1H/13C NMR technologies. Based on the synergistic mechanisms of aggregation-induced emission (AIE), excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT), it enjoyed a red-fluorescence emission at 627 nm in THF/water mixtures (fw = 95%) and was used as a probe. Moreover, the TLC-based test strips loaded with the probe not only exhibited the reversible fluorescence response to amine/acid vapor but also showed sensitive and selective fluorescence response towards Cu2+. Furthermore, the fluorescence titration experiment between the probe and Cu2+ in THF/water mixtures (fw = 95%, pH = 7.4) revealed that the detection limit was 1.18 × 10-7 M and the binding constant was 1.59 × 105. Job's plot experiment and HR-MS analysis revealed the 2:1 binding stoichiometry of the probe with Cu2+. The method enabled real-time assessment for Cu2+ in real water samples. This study could offer insightful opinions on the development of long-wavelength emissive luminogens based on α-cyanostilbene. [ABSTRACT FROM AUTHOR]

The model has been developed for the case of instantaneous nucleation and mixed kinetic-diffusion growth control of new-phase nuclei on the surface of an indifferent electrode under potentiostatic conditions. A new approach has been proposed that does not use the planar diffusion zone concept. The model provides a correct relationship between the concentration profiles to the nucleus and to the electrode due to spherical and planar diffusion, respectively. The influence of charge transfer and mass transfer parameters and the overpotential on the calculated current density transients and the average size of the nuclei has been analyzed. The simulated current density transients have been compared with the results of the calculation according to the Altimari–Pagnanelli and Scharifker–Hills models. The simulation results show that the mutual position of the current density transients under mixed control differs from that under diffusion control. It has been confirmed that the use of the dimensionless dependences of the Scharifker–Hills model at non-pure diffusion growth control can lead to serious errors in determining the mechanisms and electrocrystallization parameters. [ABSTRACT FROM AUTHOR]

New renewable energy sources, like solar cells, demonstrated to have environmental difficulties, pricing efficiency and other problems. In this study, the hole–electron theory has been applied by DFT and TD-DFT modeling to simulate an organic solar cell (OSC) with the special capabilities. This designed OSC applies a π-donor-π-acceptor system. It was demonstrated that Heme molecule could be chosen as an acceptor agent in this system. The modeled system has been modified by an efficient acceptor with four C60 fullerenes. This modeled system is considerable as an important charge and electron transfer at visible wavelengths of approximately 574 nm. The investigations were conducted in the two ground and excited states. The results have given a comprehensive picture of how the discussed OSC acts. The electron-donating part of this OSC actually consists of two S-donors that are connected by pyrazino[2,1,6-de]quinolizine linker. The energies of the all LUMO orbitals from donor part, Heme molecule, C60 and Heme + C60 (acceptor part) are cascaded from top to bottom. [ABSTRACT FROM AUTHOR]

Context: The advancement in the development of second-generation drugs in the field of antihistamines represents a significant milestone in the management of allergic diseases, targeting the effects of histamine. The efficacy of bilastine in treating allergic disorders has sparked interest in investigating its polymorphism, a crucial property that impacts quality, safety, and effectiveness as per regulatory guidelines. This study examines the polymorphism of bilastine, focusing on two crystalline forms labeled as Form I and Form II. Utilizing advanced analytical techniques, the research explores the structural characteristics and molecular interactions within these forms. Geometric parameters, such as bond lengths, bond angles, and torsion angles, are examined to comprehend molecular conformations and crystal packing arrangements. Hydrogen bonding, covalent bonds, and van der Waals forces contribute to the unique supramolecular arrangements in these forms. This study provides a significant contribution to understanding bilastine's polymorphism, offering critical insights to researchers and regulatory bodies to ensure the quality, efficacy, and safety of antihistamine products. Methods: The molecular conformation of two bilastine forms was obtained through DFT with the exchange–correlation functional M06-2X and the 6–311 + + G(d,p) basis set, and the results were compared with the experimental X-ray. The atomic coordinates were obtained directly from the crystalline structures, and charge transfer was also investigated using frontier molecular orbitals (HOMO and LUMO), and MEP map in order to evaluate the energies associated with charge transfers and regions of high electron affinity. The geometric and topological parameters and intermolecular interactions in the crystals were analyzed using Hirshfeld Surface. [ABSTRACT FROM AUTHOR]

Context: Due to their unique photophysical properties, organic charge transfer crystals are becoming promising materials for next-generation optoelectronic devices. This research paper explores the impact of s-block metals on a charge transfer crystal of indol-2-one for enhanced nonlinear optical (NLO) responses with efficient energetic offsets. The study reveals that alkali metals can enhance NLO performance due to their free electrons. Method: The Perdew-Burke-Ernzerhof functional of DFT with dispersion correction (D3) was used, and the λmax values ranged between 596 and 669 nm, with the highest value for dichloromethane (DCM). Leveraging the unique properties of metals allowed for the development of nonlinear optical materials with improved performance and versatility. Softness (σ) values provide insight into electron density changes, with higher values indicating a greater tendency for changes and lower values indicating the opposite. The NLO results for the chromophores MMI1–MMI6 show varying linear polarizability (< α0 >) along with their first (β0) and second (γ0) hyperpolarizabilities. Chromophore MMI4 stands out with the highest NLO performance, having two potassium (K) atoms. Its < α0 > , β0, and γ0 values of 4.19, 7.09, and 17.43 (× 10−24 e.s.u), respectively, indicate a significant enhancement in NLO response compared to the other chromophores. The transitions involving (O20)LP → (C3-N5)π* and (O19)LP → (N12-C13)π* exhibit the highest level of stabilization, followed by (O23)π → (C10-C11)π*, while (C6-N12)π → (C6-C7)π* shows the lowest level of stabilization for chromophore MMI4. The present research work is facile in its nature, and it can be helpful for synthetic scientist to design the new materials for uniting crystal properties with metal doping for efficient NLO devices. [ABSTRACT FROM AUTHOR]

Context: Push–pull compounds are model systems and have numerous applications. By changing their substituents, properties are modified and new molecules for different applications can be designed. The work investigates the gas-phase electronic absorption spectra of 15 derivatives of push–pull para–nitroaniline (pNA). This molecule has applications in pharmaceuticals, azo dyes, corrosion inhibitors, and optoelectronics. Both electron-donor and electron-withdrawing groups were investigated. Employing machine learning–derived Hammett's constants σm, σm0, σR, and σI, correlations between substituents and electronic properties were obtained. Overall, the σm0 constants presented the best correlation with HOMO and LUMO energies, whereas the σR constants best agreed with the transition energy of the first band and HOMO–LUMO energy gap. Electron-donors, which have lower σR values, redshift the absorption spectrum and reduce the HOMO–LUMO energy gap. Conversely, electron-withdrawing groups (higher σR's) blueshift the spectrum and increase the energy gap. The second band maximum energies, studied here for the first time, showed no correlation with σ but tended to increase with σ. A comprehensive charge transfer (CT) analysis of the main transition of all systems was also carried out. We found that donors (lower σ's) slightly enhance the CT character of the unsubstituted pNA, whereas acceptors (higher σ's) decrease it, leading to increased local excitations within the aromatic ring. The overall CT variation is not large, except for pNA–SO2H, which considerably decreases the total CT value. We found that the strong electron donors pNA–OH, pNA–OCH3, and pNA–NH2, which have the smallest HOMO–LUMO energy gaps and lowest σ's, have potential for optoelectronic applications. The results show that none of the studied molecules is fluorescent in the gas phase. However, pNA–NH2 and pNA–COOH in cyclohexane and water reveal fluorescence upon solvation. Methods: We investigated theoretically employing the second-order algebraic diagrammatic construction (ADC(2)) ab initio wave function and time-dependent density functional theory (TDDFT) the gas-phase electronic absorption spectra of 15 derivatives of p–nitroaniline (pNA). The investigated substituents include both electron-donor (C6H5, CCH, CH3, NH2, OCH3, and OH,) and electron-withdrawing (Br, CCl3, CF3, Cl, CN, COOH, F, NO2, and SO2H) substituents. [ABSTRACT FROM AUTHOR]

Context: In this study, we have developed four new chromophores (TM1–TM4) and performed quantum chemical calculations to explore their nonlinear optical properties. Our focus was on understanding the impact of electron-donating substituents on 1,3,4-oxadiazole derivative chromophores. The natural bond orbital analysis confirmed the interactions between donors and acceptors as well as provided insights into intramolecular charge transfer. We also estimated dipole moment, linear polarizability molecular electrostatic potential, UV–visible spectra, and first hyperpolarizability. Our results revealed that TM1 with a strong and stable electron-donating group exhibited high first hyperpolarizability (β) 293,679.0178 × 10−34 esu. Additionally, TM1 exhibited a dipolar moment (μ) of 5.66 Debye and polarizability (α) of 110.62 × 10−24 esu when measured in dimethyl sulfoxide (DMSO) solvent. Furthermore, in a benzene solvent, TM1 showed a low energy band gap of 5.33 eV by using the ωB97XD functional with a 6–311 + + G(d, p) basis set. Moreover, our study of intramolecular charge transfers highlighted N, N dimethyl triphenylamine and carbazole as major electron-donating groups among the four 1,3,4-oxadiazole derivative chromophores. This research illustrates the potential applications of these organic molecules in photonics due to their versatile nature. Methods: The molecules were individually optimized using different functionals, including APFD, B3LYP, CAM B3LYP, and ωB97XD combined with the 6–311 + + G (d, p) basis set in Gaussian 16 software. These methods encompass long-range functionals such as APFD and B3LYP, along with long-range corrected functionals like CAM B3LYP and ωB97XD. The employed functionals of APFD, B3LYP, CAM B3LYP, and ωB97XD with the 6–311 + + G (d,p) basis set were used to extract various properties such as geometrical structures, dipole moment, molecular electrostatic potential, and first hyperpolarizability through precise density functional theory (DFT). Additionally, TD-DFT was utilized for obtaining UV–visible spectra. All studies have been conducted in both gas and solvent phases. [ABSTRACT FROM AUTHOR]

Supercapacitors and water splitting cells have recently played a key role in offering green energy through converting renewable sources into electricity. Perovskite-type electrocatalysts such as BaTiO3, have been well-known for their ability to efficiently split water and serve as supercapacitors due to their high electrocatalytic activity. In this study, BaTiO3, Al-doped BaTiO3, Ce-doped BaTiO3, and Al-Ce co-doped BaTiO3 nanofibers were fabricated via a two-step hydrothermal method, which were then characterized and compared for their electrocatalytic performance. Based on the obtained results, Al-Ce co-doped BaTiO3 electrode exhibited a high capacitance of 224.18 Fg−1 at a scan rate of 10 mVs−1, high durability during over the 1000 CV cycles and 2000 charge–discharge cycles, proving effective energy storage properties. Additionally, the onset potentials for OER and HER processes were 11 and − 174 mV vs. RHE, respectively, demonstrating the high activity of the Al-Ce co-doped BaTiO3 electrode. Moreover, in overall water splitting, the amount of the overpotential was 0.820 mV at 10 mAcm−2, which confirmed the excellent efficiency of the electrode. Hence, the remarkable electrocatalytic performance of the Al-Ce co-doped BaTiO3 electrode make it a promising candidate for renewable energy technologies owing to its high conductivity and fast charge transfer. [ABSTRACT FROM AUTHOR]

The adsorption properties of benzyl chloride and benzyl bromide on tetragonal silicane (tetra-silicane) are studied based on the density functional theory. The tetra-silicane possesses a stable structure with an energy band gap of 2.887 eV. Besides, the hydrogenation along the vertical directions increases the band gap of tetra-silicane suitable as an adsorbing material for benzyl chloride and benzyl bromide molecules. We observed the changes in the electronic properties of tetra-silicane due to target molecules' adsorption, which is evident from charge transfer, electron density difference diagrams, band structure, and projected density of states spectrum. The tetra-silicane exhibits chemo-resistive properties owing to benzyl chloride and benzyl bromide molecular adsorption. The current report will open the gate in the new sensing material towards benzyl chloride and benzyl bromide molecules, which are classified under chemical warfare agents. [ABSTRACT FROM AUTHOR]

An original zero-dimensional 1, (2-aminoethyl) piperazinuim) tetrabromidomercurate (II) monohydrate (C6H17N3)[HgBr4].H2O monomer has been isolated from the response of mercuric chloride (HgCl2) with the organic base, H2O, and HBr under ambient conditions. The crystal system of the complex is orthorhombic, space group P c a 21 with the grid parameters a = 16.7471(5) Å, b = 6.7179(2) Å, c = 13.9445(3) Å, α = 90°, β = 90°, γ = 90°, V = 1568.83(7) Å3, Z = 4, and R = 0.0415. This work does the symmary and determination of the initial zero-dimensional crystal structure in aqueous media under ambient conditions. IR spectroscopy confirmed the presence of organic cations, and UV spectroscopy was also conducted to identify the complex. Hirshfeld surface analysis and associated two-dimensional fingerprints for the study and quantification of intermolecular interactions in crystal and to determine charge transfer inside the structure, the HOMO/LUMO analysis was purposed. Geometric optimization and electronic, topological, and biological activity were theoretically investigated using DFT, and potential biological activity was investigated using molecular docking analysis. [ABSTRACT FROM AUTHOR]

In this study, we investigate the effectiveness of murexide for surface modification of Fe 3 O 4 nanoparticles to enhance the performance of multiwalled carbon nanotube- Fe 3 O 4 supercapacitor anodes. Our experimental results demonstrate significant improvements in electrode performance when murexide is used as a capping or dispersing agent compared to the case with no additives. When murexide is used as a capping agent, we report a capacitance of 4.2 F cm - 2 from cyclic voltammetry analysis with good capacitance retention at high scan rates. From impedance measurements, we reveal a substantial decrease in the real part of impedance for samples prepared with murexide, indicating easier charge transfer at more negative electrode potentials, and reinforcing the role of murexide as a capping agent and charge transfer mediator. Density functional theory is used to investigate interactions between the murexide adsorbate and the Fe 3 O 4 (001) surface, with a specific emphasis on adsorption strength, charge transfer, and electronic properties. This theoretical investigation uncovers a strong adsorption enthalpy of − 4.5 eV and allows us to identify the nature of chemical bonds between murexide and the surface, with significant charge transfer taking place between the Fe 3 O 4 surface and murexide adsorbate. The transfer of electrons from the Fe 3 O 4 surface to murexide is recognized as a vital component of the adsorption process. By examining the bonding nature of murexide on Fe 3 O 4 , this research study uncovers insights and proposes a novel bonding configuration of murexide that incorporates a combination of bridging and chelating bonding. [ABSTRACT FROM AUTHOR]

The curcuminoid class of organic compounds is very versatile which possesses applications over vast fields of science and technology. In the present investigation, we systematically designed six curcuminoid (Crmd) derivatives with symmetric and asymmetric structures, which are named as Crmd-1 to Crmd-6. We used 2,2-difluoro-4,6-divinyl-dioxaborinine moiety as a linker to design symmetric and asymmetric donor π-conjugation and acceptor configurations. Triphenylamine and triphenylborane are used as donor and acceptors which are intrinsically donor and acceptors owing to the presence of vacant p-orbital in boron and lone pair of electrons in nitrogen atoms, respectively. Density functional theory (DFT) is applied using M06/6-311G* method to calculate linear polarizability (α), and second hyperpolarizability (γ). The value of isotropic linear polarizability (αiso) and anisotropic linear polarizability (αiso) are 125.3 × 10–24 esu and 148.1 × 10–24 esu for Crmd-6, respectively. By comparative analysis, it is observed that the highest value of γ amplitude is calculated to be 6472.3 × 10–36 esu for Crmd-6. The robust increase in non-linear optical (NLO) polarizability is observed due to the asymmetric intramolecular charge transfer (ICT) and better D-π-A configuration in Crmd-6. Time dependent DFT calculations are performed to observe the origin of third-order NLO polarizabilities. Furthermore, frontier molecular orbitals, electron density difference, molecular electrostatic potential diagrams, and transition density matrix analysis demonstrate enhanced charge redistribution from the donor to the acceptor fragments. The use of modern computational tools highlights an effective ICT, which leads stronger third-order NLO response properties in designed curcuminoid derivatives. [ABSTRACT FROM AUTHOR]

Promising charge transfer (CT) complexes were prepared to be used as: solid conducting electrolytes for batteries voltaic cells, biosensors, biochips, diagnostic applications and the electronic devices. Charge transfer (CT) complexes generated between electron Schiff bases donor of Aryl 2-azomethine dibenzothiophene-Schiff base, 1,3-dinitrobenzene (A1), 2,4-dinitrophenol (A2) and picric acid (A3) as-acceptors have been studied using spectroscopic kinetic investigations. The reactions of the donor and the acceptor compounds were followed at different temperatures (20, 30, 40 and 50 °C) and in the range of time between 0 and 55 min. The rate of formation of the product (k) and the molar extinction coefficient (ε) has been calculated and discussed. The activation energy (Ea) has been calculated from the first-order kinetic equation. The thermal dehydration and decomposition of these complexes were studied kinetically using the integral method applying the Coats–Redfern, Ozawa and composite methods. These donor–acceptor charge transfer complexes have a promising antimicrobial activity comparable to the corresponding schiff base compound. TGA-DTA and DSC studies were also carried out to check the stability of CT complex, and activation energy (Ea) has been calculated. These donor–acceptor charge transfer complexes and the attributed of N, O and S atoms have a promising antimicrobial activity that suggested the applications of this class of compounds in pharmaceutical and medical applications. The antibacterial and antifungal activities of the synthesized charge transfer complexes were screened against and fungi (Candida) bacterial species (Escherichia coli and Staphylococcus aureus). The activity data show that the CT complexes have a promising biological activity comparable to the Schiff base compound against bacterial and fungal species. These CT complexes comparable to the corresponding schiff base compound have semiconducting and piezoelectric properties electronic conductivity. The piezoelectric polarization is induced due to the reorientation of the polar groups and its dipoles. The phase transition on heating the complexes reflects the dielectric nature due to the defect and the transport properties. [ABSTRACT FROM AUTHOR]

The production of ammonia (NH3) from nitrogen (N2) in mild electrochemical conditions is of prime importance to obtaining sustainable fertilizers and carbon-free energy conversion, which strongly depends on the electronic occupation state at reactive sites. Herein, the structural symmetry breaking is regulated to rearrange spin electron configuration in an effort to optimize the reaction pathway of nitrogen reduction. The structure distortion is achieved in multistage-coupled BiErRu2O7 pyrochlores by controlling the bonding interaction from Bi-6s lone pair electrons. The results demonstrate that the structural symmetry breaking can effectively optimize the bonding interaction and charge transfer between active sites and reactants, finally leading to the selection of reaction pathway from N2 to NH3. The structural symmetry breaking is regulated to rearrange spin electron configuration in multistage-coupled BiErRu2O7 pyrochlores, which can effectively optimize the bonding interaction and charge transfer between active sites and reactants, finally leading to the selection of reaction pathway from N2 to NH3. [ABSTRACT FROM AUTHOR]

Context: It has been reported that photoexcitation of azastilbene compounds like E-1,2-bispyrazinyl-ethylene (bpe) can undergo E → Z photoisomerization of its quaternary salts via the excited triplet state. However, experimentally it is possible to get low fluorescence and photoisomerisation quantum yields in a state with higher internal conversion than intersystem crossing. We modelled bpe and its methylated derivative (bpeMe), as well as its quaternary halogen salts (bpeMeX with X = F−, Cl−, Br− and I−) to study levels of fluorescence, phosphorescence and excited state potential energy surfaces (PES). Results support experimental observations of molecules where the anion of a salt is an efficient electron donor, that molecules with weak electron-donating anions like Cl− to give increased fluorescence and photoisomerization, as compared to molecules with stronger electron-donating anions like I−, which are dominated by competing electron transfer. The fluorescence of bpeMeF and bpeMeCl was found to be stronger than bpeMeBr and bpeMeI. A deep well in the triplet excited state of bpeMeI is considered responsible for the decreased photoisomerization, compared to what was experimentally observed for bpeMeCl. Uniquely, the bpeMeI molecule is characterised by near-zero splitting of the s1 and t1 excited states that can enhance charge transfer. The quaternary salt of bpeMe with stronger electron-donating Br− anion was observed to undergo fluorescence and phosphorescence at much lower energy compared to those with weak electron-donating F− and Cl− anions. This research shows how to control the excited state fluorescence, phosphorescence and isomerization of quaternary halogen salts of methyl derivatives of 1,2-bispyrazinyl-ethylene, which aids experimental design where excited state isomerization is considered. Methods: Geometry optimization, molecular electrostatic potential (MESP), and time dependent density functional theory (TDDFT) calculations were conducted utilizing Gaussian 16 with the B3LYP functional and the 6–31 + G(d,p) basis set. The minimum energy path (MEP) for the E to Z isomerization of the molecules was established employing the Nudged-Elastic-Band (NEB) method, implemented in Orca 4.2. Precise energies of the E → Z isomerization reaction path were determined employing CASSCF and a more accurate multireference method, NEVPT2. [ABSTRACT FROM AUTHOR]

Context: A comparative study of the change in different properties of electronic and structural of the free 1H-indole-2,3-dione molecule and its complexes has been obtained. HOMA analysis was performed to investigate the effects of lithium sodium and potassium cations on the aromaticity of lithium sodium and potassium complexes of 1H-indole-2,3-dione. Methods: Several 1H-indole-2,3-dione complexes with lithium, sodium, and potassium cations were optimized at the B3LYP/6-311G(d,p) level. The cation and π interaction has been investigated from different aspects, including interaction energy calculations, charge transfer values, and changes in the aromaticity of the ring upon complexation. The charge transfer and natural population analysis for the complexes were performed with the natural bond orbital (NBO) analysis. The properties of bond critical points in complexes were studied by applying the quantum theory of atoms in molecules (QTAIM). Finally, the aromaticity change of phenyl induced upon complex formation was evaluated by applying the harmonic oscillator model of aromaticity (HOMA). [Li-INa]+ and [[Li-INb]+ were optimized with the wB97XD function using a version of Grimme’s D2 dispersion model, and the absorption energy was compared with the calculation made with the B3LYP functional. [ABSTRACT FROM AUTHOR]

Naphthalimide—styrylpyridine-, styrylpyridine—styrylpyridine-, and naphthalimide—naphthalimide-type bichromophoric chemosensors for metal cations were obtained. Their photoactive fragments were linked by an open-chain oligoethylene glycol spacer, which acted as a receptor group. Optical and NMR spectroscopy was used to show that these compounds can form complexes with calcium and barium cations in an acetonitrile solution. In the case of an "asymmetric" bichromophore, the binding of these cations was accompanied by a redshift of the absorption and emission bands of styrylpyridine, a decrease of the efficiency of resonance energy transfer in the system, and an increase in the intensity of the fluorescence band of the naphthalimide residue. Complexation led to a hypsofluoric shift of the maximum in the fluorescence spectrum of the "symmetric" bis(styryl-pyridine). In both cases, spectral changes made it possible to register a ratiometric fluorescent response to the presence of metal cations in the solution. [ABSTRACT FROM AUTHOR]

Nanocomposite nanozeolite/acetylene carbon black was prepared by combining a type A zeolite with acetylene carbon black (AcB) and used to modify glassy carbon electrode (GCE) without polymer. The zeolite was prepared by hydrothermal method using natural kaolin. The physicochemical characterization of the composite showed a well-integrated composite in which the cubic crystal of the zeolite A and the graphitic aggregate of the carbon black were maintained. The electrochemical impedance spectroscopy study revealed that the composite film GCE (ZA-AcB/GCE) prepared by drop coating displayed a higher kinetic charge transfer compared to pristine zeolite modified GCE (ZA/GCE) and bare GCE. ZA-AcB/GCE, ZA/GCE and GCE were subsequently used to investigate the electrochemical behaviour of acetaminophen (AC) in acidic, neutral and alkaline pHs. The results demonstrate a good electrocatalytic property toward AC at composite film GCE in all these electrolytes compared to bare GCE and confirm the dependence of the electrochemical reaction mechanism of AC on the electrolyte's pHs. Under optimal conditions, ZA-AcB/GCE exhibited higher sensitivity and selectivity toward both analytes taken individually or simultaneously within large concentration range: 0.5–89 µM for AC and 5–99 µM for caffeine (CAF) with the respective limit of detection of 0.38 and 0.82 µM. The developed sensors were applied successfully in the quantification of the both analytes in pharmaceutical tablets. [ABSTRACT FROM AUTHOR]

Electrochemiluminescence (ECL) is a luminescence production technique triggered by electrochemistry, which has emerged as a powerful analytical technique in bioanalysis and clinical diagnosis. During ECL, charge transfer (CT) is an important process between electrochemical excitation and luminescent emission, and dramatically affects the efficiency of exciton generation, playing a pivotal role in the light-emitting properties of nanomaterials. Reticular framework materials with intramolecular/intermolecular interactions offer a promising platform for regulating CT pathways and enhancing luminescence efficiency. Deciphering the role of intramolecular/intermolecular CT processes in reticular framework materials allows for the targeted design and synthesis of emitters with precisely controlled CT properties. This sheds light on the microscopic mechanisms of electro-optical conversion in ECL, propelling advancements in their efficiency and breakthrough applications. This mini-review focuses on recent advancements in engineering CT within reticular frameworks to boost ECL efficiency. We summarized strategies including intra-reticular charge transfer, CT between the metal and ligands, and CT between guest molecules and frameworks within reticular frameworks, which holds promise for developing next-generation ECL devices with enhanced sensitivity and light emission. [ABSTRACT FROM AUTHOR]

Organic–inorganic halide perovskites have shown great potential for the conversion of solar energy to hydrogen fuel via photocatalytic reaction due to their excellent optoelectronic properties. However, one of the biggest challenges for organic–inorganic halide perovskite materials in photocatalytic hydrogen evolution reaction (HER) lies in the serious recombination of photogenerated electron and hole pairs. Herein, we reported that the coupling of nickel phosphide (Ni2P) nanoparticles with methylammonium lead halide (MAPbI3) perovskite can significantly enhance the photocatalytic H2 evolution performance of MAPbI3. We found that Ni2P coupling can promote the electron exaction from MAPbI3, thereby accelerating the charge transfer and retarding the charge recombination. Moreover, Ni2P particles exhibited good electrocatalytic activity for the HER. Consequently, the Ni2P/MAPbI3 composite exhibited ca. 459 times higher activity than the parent MAPbI3 in photocatalytic HI splitting reaction. Moreover, the Ni2P/MAPbI3 composite exhibited excellent stability during cycling tests. This work demonstrated the potential of using Ni2P as non-noble metal-based co-catalyst to promote the photocatalytic performance of organic–inorganic halide perovskite. [ABSTRACT FROM AUTHOR]

Graphene is extremely sensitive to its surrounding environment. In fact, any modification on its surface, such as an adsorption of a molecule, can change its properties. The conductivity of graphene is a crucial parameter to be examined for potential graphene-based applications, especially biosensors. In this paper, we have investigated the effects of non-covalent functionalization based on π–π interaction, using 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE), on the conductivity of graphene-based electrodes by electrochemical techniques. Graphene layers were obtained by chemical vapor deposition (CVD) and characterized by Raman spectroscopy, Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). The results demonstrate the synthesis of a high quality and continuous monolayer graphene with an I2D/IG ratio = 2.71 and ID = 0. After the functionalization of graphene-based electrode with PBASE, the electrochemical analyses confirmed a p-doping effect existence influencing the conductivity by increasing the charge transfer resistance Rct from 816.5 to 2213 Ω. Furthermore, increasing the concentration of PBASE from 5 mM to 10 mM did not affect the conductivity as the Rct did not change. Solvent adsorption was found to be the main cause of the decrease in conductivity during the functionalization process. This study highlights the effect of non-covalent π-π stacking of PBASE on graphene to tune the electrical properties of graphene through functionalization processes for a better performance for their use as biosensors. [ABSTRACT FROM AUTHOR]

This paper describes initially the application of the Tyndall effect (TE) of metal–organic framework (MOF) materials as a colorimetric signaling strategy for the sensitive detection of pyrophosphate ion (PPi). The used MOF NH2-MIL-101(Fe) was prepared with Fe3+ ions and fluorescent ligands of 2-amino terephthalic acid (NH2-BDC). The fluorescence of NH2-BDC in MOF is quenched due to the ligand-to-metal charge transfer effect, while the NH2-MIL-101(Fe) suspension shows a strong TE. In the presence of PPi analyte, the MOFs will undergo decomposition because of the competitive binding of Fe3+ by PPi over NH2-BDC, resulting in a significant decrease in the TE signal and fluorescence restoration from the released ligands. The results demonstrate that the new method only requires a laser pointer pen (for TE creation) and a smartphone (for portable quantitative readout) to detect PPi in a linear concentration range of 1.25–800 μM, with a detection limit of ~210 nM (3σ) which is ~38 times lower than that obtained from traditional fluorescence with a spectrophotometer (linear concentration range, 50–800 µM; detection limit, 8.15 µM). Moreover, the acceptable recovery of PPi in several real samples (i.e., pond water, black tea, and human serum and urine) ranges from 97.66 to 119.15%. [ABSTRACT FROM AUTHOR]

This work employs a straightforward, simple and low-cost method to grow g-C3N4 quantum dots (QDs) on a distinctive morphology of urchin-like TiO2 (u-TiO2) nanostructures. u-TiO2 on Ti foil was prepared by the hydrothermal method under the optimized experimental parameters, including hydrothermal time and temperature. Then, for the activation of u-TiO2 under visible light irradiation, g-C3N4 quantum dots (g-C3N4 QDs) were decorated on u-TiO2 by combining a wet pre-coating and subsequent thermal evaporation procedure. The experimental parameters of the process were examined to determine the optimized conditions for the highest photocurrent density (Jph) in a photoelectrochemical (PEC) cell. g-C3N4 QDs were elucidated by transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS). HRTEM results revealed a uniform distribution of anchored g-C3N4 QDs on the surface of u-TiO2 with a mean size of about 10 nm. Optimized decoration of g-C3N4 QDs on the u-TiO2 dramatically enhanced Jph under simulated sunlight irradiation from 0.06 mA/cm2 for pristine u-TiO2 up to 0.12 mA/cm2 for TiO2/g-C3N4QDs photoanodes under the biased potential of 0.5 V versus Ag/AgCl. Based on the results, the type-II heterostructure of u-TiO2/g-C3N4 facilitates electron–hole separation and charge carrier transfer, thereby improving the PEC performance of the proposed photoanode. [ABSTRACT FROM AUTHOR]

We investigate the nonlinear optical response of Pb2+-doped ZnMoO4 nanostructures synthesized by chemical precipitation technique. X-ray diffraction (XRD) and Raman spectroscopy results confirm the formation of ZnMoO4 nanostructures with a triclinic structure. High-Resolution Transmission electron microscope (HRTEM) reveals the deformed spherical shape of nanostructures. Further, the successful doping and molecular bonding of Pb2+ with ZnMoO4 was evidenced by FTIR and XPS. UV–Vis absorption spectra reveals the alteration in the electronic band structure of ZnMoO4 nanostructures upon Pb doping, leading to a considerable increase in bandgap and enhanced charge transfer within ZnMoO4: Pb nanostructure. The nonlinear optical absorption and optical limiting characteristics of the nanoparticles is measured via the open aperture Z-scan technique with an Nd: YAG pulsed laser at 532 nm, exhibiting a reverse saturable absorption and a rapid decrease in the commencement of the optical limiting threshold with the increased in Pb concentration. The observed nonlinear absorption can be attributed to the crystal structure, particle size, creation of oxygen vacancies, and defects on the host lattice. These results suggest that Pb2+-doped ZnMoO4 nanoparticles have excellent prospects for optical limiting (OL) applications. This could be useful for applications such as laser protection and optoelectronic device applications. [ABSTRACT FROM AUTHOR]

Efficient photocatalytic performance plays a pivotal role in tackling our present energy challenges. A well-designed arrangement of nanoscale semiconductors and metallic components within multi-heterojunction photocatalysts can establish rapid transport pathways, enhancing the separation and migration of charge carriers. This approach offers a viable strategy towards achieving optimal photocatalytic efficiency. Herein, the glancing angle deposition technique (GLAD) technology of electron beam evaporation and spin-coating method were used to construct Fe2O3/TiO2/WO3/Ti3C2Tx quaternary composite materials with serial heterojunctions. Photocatalytic activity was assessed through photoelectrochemical tests, revealing that the Fe2O3/TiO2/WO3/Ti3C2Tx composite material outperformed its counterparts under visible-light irradiation. Notably, it achieved the highest photocurrent response, with a maximum photocurrent density of 1.09 mA/cm2. This represented a substantial improvement, surpassing Fe2O3, Fe2O3/TiO2, and Fe2O3/TiO2/WO3 photocatalysts by factors of 36, 2.8 and 1.25, respectively. This remarkable enhancement can be attributed to the formation of three heterojunctions in series, creating multiple pathways for efficient charge transfer and separation during the photocatalytic process. Furthermore, we proposed a photocatalytic mechanism for quaternary heterojunctions based on band structure analysis. [ABSTRACT FROM AUTHOR]

A series of α-cycloamine substituted 2,2'-bipyridines 3ae'-3ce' was obtained via the one-pot approach based on ipso-substitution of a cyano-group in 1,2,4-triazines, followed by aza-Diels–Alder reaction in good yields. Photophysical properties, including fluorosolvatochromism, were studied for 3ae'-3ce' and were compared with α-unsubstituted 2,2'-bipyridines. In addition, dipole moments differences in ground and excited states were calculated by both Lippert-Mataga equation and DFT studies and were compared to each other. The correlation between the size of cycloamine unit and the dipole moments differences value (based on Lippert-Mataga equation) was observed. In addition charge transfer indices (DCT, Λ, H and t) were calculated to demonstrate influence of molecular structure on the intramolecular charge transfer degree. [ABSTRACT FROM AUTHOR]

The present work intended to report the synthesis of newly designed donor-acceptor complexes of the pyrimidine-based system namely TAPHIA 1 and TAPHIA 2, which are symphonized to give the NLO properties. The methodologies adopted for both complexes were different and hence influenced their geometrical properties. The synthesized complexes were characterized using different techniques including SCXRD, FTIR, UV, PXRD, and TGA to confirm their formation. The SCXRD analysis revealed that TAPHIA 1 was crystallized in the Pca21 space group in an orthorhombic system while TAPHIA 2 was crystallized in the P21/c space group in a monoclinic system. The third-order NLO properties of both complexes were explored using the Z-Scan technique by employing a continuous wave (CW) diode laser of 520 nm. The third-order NLO parameters including nonlinear refractive index (n2), nonlinear absorption coefficient (β) and nonlinear optical susceptibility (χ (3)) were calculated at different powers; 40, 50 and 60 mW at fixed solution concentration (10 mM) for both the complexes. Moreover, the experimental properties including NLO, FTIR, and UV were well corroborated with theoretical results obtained at the B3LYP-D3/6-31++G(d,p) level of theory. The analysis of the theoretical and experimental properties of both complexes suggests that TAPHIA 2 is a better applicant to be employed in optical devices than TAPHIA 1 due to the enhanced ability of internal charge transfer. Symphonizing effect of NLO properties exhibited by two newly synthesized donor acceptor complexes namely TAPHIA 1 and TAPHIA 2. The NLO potential of the two newly reported organic complexes were influenced by their structural properties and charge transfer ability, made them good applicants to be employed in optoelectronic field. [ABSTRACT FROM AUTHOR]

In this study, we investigated the impact of incorporating small organic molecules p-nitrobenzylinemalononitrile (NO2BMN) into a poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2′,1′,3′-benzothiadiazole] (PCDTBT) matrix on the optical and electrical proprieties. The absorption and photoluminescence spectra were used to confirm the improvement of the optical characteristics. An optimal weight ratio of (1:1) of PCDTBT:NO2BMN composite is found to achieve the best efficiency of charge transfer that occurs between both compounds. For the same composition, the device based on ITO/PCDTBT:NO2BMN/Al structure shows an improvement in current density and reduction in threshold voltage. Additionally, we have estimated the conduction mechanisms by the analyses of J (V) characteristics in a double logarithmic scale under dark conditions. The obtained results indicated that the addition of NO2BMN enhances the electrical properties of the composite. [ABSTRACT FROM AUTHOR]

Many research studies have been carried out on various nanostructures regarding their potential applications in drug delivery for treating different cancers. In fact, the serious side effects can be minimized by delivering various anticancer drugs to particular tumour cells. Within the present study, the ability of a pure AlN nanotube (PAlN-NT) and X-decorated (X = Au, Pt and Ir) AlN-NT to deliver the anticancer levodopa (LVP) drug is inspected through DFT computations. The results demonstrate that PAlN-NT is not suitable for the drug delivery of LVP. Decoration of the Au, Pt and Ir metals into the AlN-NT, respectively, raised the adhesion energy (Ead) of LVP from −4.3 to −27.2, −28.1 and −29.5 kcal mol−1. Ead for LVP/Ir-decorated AlN-NT structures is approximately −26.8 kcal mol−1 in the aqueous phase. Moreover, there is a substantial amount of charge transfer from LVP to the surface of the X-decorated AlN-NT based on the NBO analysis. Hence, based on the computations undertaken within this work, the X-decorated AlN-NT, especially Ir-decorated AlN-NT, can be utilized as a suitable LVP carrier. [ABSTRACT FROM AUTHOR]

Fabrication of composite photocatalysts that provide an easy charge transfer mechanism to enhance the photocatalytic activity is a promising approach for the removal of organic contaminants from the water bodies. In this series, for the first time, we have decorated Ni, Pt, and Pd on the surface of hydrothermally synthesized Cu-doped biphasic Bi2O3. The synthesized composites were analyzed using advanced characterization techniques to uncover the physicochemical properties of the materials. The XRD results revealed well crystalline nature of the materials with enhanced particle size as compared to binary composite. The optical analysis showed the improved optical characteristics of ternary composites. The photocatalytic activity was tested against the RhB and observed the ternary materials with enhanced activity when compared with the binary composite and 5 wt% was the optimum loading of the metal on the surface of Cu- doped Bi2O3. Pd decorated samples showed the highest photo removal of RhB where complete mineralization of dye is achieved only in 50 min which is ascribed to the increased absorption and reduced reunion of charge carriers. The effect of pH of the reaction medium and the role of reactive oxygen species were also examined. In the acidic medium, complete degradation of dye is achieved in 10 min only and holes are found prominent active species for the degradation of RhB. The synthesized materials were stable and could be used many times without significant loss in the photocatalytic activity. [ABSTRACT FROM AUTHOR]

The understanding of the implication of the transport of matter is fundamental in the teaching of heterogeneous charge transfers, which are the central element of the electrochemical science and technologies. Thus, even in the absence of intrinsic kinetic complications, the overall rate of such events is frequently conditioned by the mass transport and also by the occurrence of homogeneous coupled chemical reactions. Upon comprehending and accounting for these two effects, the emergent and widely used concepts of the diffusion and reaction layers will be discussed and disentangled under potential-controlled conditions. First, some basic concepts about the transport of charged species in solution are recalled, in order to establish the experimental conditions under which diffusion-only transport can be considered. Under these premises, a fast electron transfer will be considered to introduce the concept of "diffusion layer", discussing its relationship with the time of the experiment and with the characteristics of the diffusive field that is strongly influenced by the geometry and size of the electrode considered. Next, fast electron transfer reactions "conditioned" by homogeneous chemical reactions undergone by the reactant and/or the product of the redox couple will be analysed. A historical introduction to the concept of "reaction layer" is carried out, pointing out its value in processes with chemical regeneration of the electroactive species and its non-negligible interplay with the mode of diffusion. [ABSTRACT FROM AUTHOR]