Spectroscopic Techniques Research Articles

Enhanced visible-light-driven photocatalytic potential of magnetic NiMnFeO4/g-C3N4 nanocomposites for degradation of aqueous organic pollutants: Schiff-base ligand-assisted sol–gel auto-combustion synthesis, characterization and mechanism analysis

Globally, the contamination of aquatic systems and wastewater by dyes is highlighted as a critical concern for human beings. Therefore, it is necessary to construct novel heterostructure photocatalysts with broadened light absorption range and enhanced charge transfer rates. The primary objective of this research is to achieve the NiMnFeO4 phases through an auto-combustion route with exploring various Schiff base ligand’s effects such as H2Salen, H2Salpn, and H2Salophen on crystalline structural and morphological features. Following this, a composite of NiMnFeO4 nanoparticles and graphitic carbon nitride (g-C3N4) nanosheets was synthesized via a sonochemical-assisted co-precipitation process, in which diverse weight proportions of nano-NiMnFeO4 was employed. To unveil the crystalline structure, chemical composition, morphology and magnetic properties of NiMnFeO4/g-C3N4 nanocomposites, multiple spectroscopic and microscopic techniques were carried out. The outcomes displayed that pure NiMnFeO4 phase synthesized in the presence of H2Salpn have optical bandgap energy of 2.0 eV and morphologically desirable nano-sample. The photocatalytic efficiencies and kinetic investigation of as-obtained NiMnFeO4, g-C3N4 and various NiMnFeO4/g-C3N4 nanocomposite’s types were perused through degradation of cationic malachite green and anionic eosin dyes under visible light irradiation. The content of nano-NiMnFeO4 in binary component systems changed the yields of the photocatalytic process and NiMnFeO4/g-C3N4 (0.25:1) nanocomposites revealed highest eosin degradation proficiency (95.12%) in visible region after 120 min. Furthermore, the proposed mechanism underlying eosin degradation via photocatalytic activity was thoroughly investigated via reactive species scavenging experiments. In photoreactions conducted by optimum NiMnFeO4/g-C3N4 (0.25:1) sample, both hydroxyl and superoxide radicals performed the superior role for the photocatalytic breakdown of eosin below visible lamp.

Surface-induced adsorption of carbon black/metal organic framework composites for methylene blue dye

ABSTRACT The present work describes the photocatalytic degradation of methylene blue (MB) dye using a newly developed composite prepared by integration of Zirconium-based metal-organic frameworks (Zr-MOF) and carbon black (CB). In this research, the Zr-MOF/CB composite was prepared by sonication and characterized by spectroscopic techniques like X-Ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FT-IR), Photoluminescence (PL), and Ultraviolet-Visible Spectroscopy (UV-VIS). In the present research, a series of photodegradation experiments were conducted to assess the efficiency of the Zr-MOF/CB composite as a photo catalyst for the degradation of MB dye under sunlight light irradiation. More specifically, the efficiency of solution pH on photo degradation efficiency was also examined. The results indicated that the Zr-MOF/CB composite had better photocatalytic activity than pristine Zr-MOF. This effect resulted from the interaction between Zr-MOF and carbon black, due to enhanced light absorption and charge carrier separation. The degradation was studied using a UV-VIS spectrophotometer, and reaction kinetics were studied using pseudo-zeroth, first and second order. In general, the Zr-MOF/CB composite shows promising potential as a proficient photocatalyst for the treatment of wastewater contaminated with MB dye.

Coumarin hybrids: dual-target candidates for future antimicrobial and antitubercular therapies.

This study aimed to synthesize, characterize, and evaluate the antimicrobial and antitubercular activities of two novel series of coumarin-based derivatives (Series 5 and Series 9), focusing on their structure-activity relationship (SAR) and molecular docking interactions with key bacterial enzymes. Series 5 (5a-5j) and Series 9 (9a-9t) compounds were synthesized and characterized using spectroscopic techniques. Their antimicrobial and antitubercular activities were evaluated against Mycobacterium tuberculosis, Staphylococcus aureus, Bacillus subtilis, and E. coli. IC₅₀ values were determined, and molecular docking studies were conducted to assess binding interactions with M. tuberculosis enoyl-ACP reductase (InhA) and E. coli DNA gyrase B. Series 5 compounds exhibited moderate activity, with 5f, 5 g, 5i, and 5j showing notable inhibition. Series 9 derivatives displayed superior dual-target inhibition, with 9t, 9c, 9a, 9b, and 9p achieving >90% inhibition against S. aureus and B. subtilis. The lowest IC₅₀ against M. tuberculosis was observed for 9c (1.50 µg/mL), followed by 9a (2.84 µg/mL) and 9b (2.73 µg/mL). Molecular docking confirmed strong binding interactions, correlating with observed biological activities. Series 9 compounds, particularly 9t, 9c, and 9a, demonstrate high potential as dual-target antimicrobial drug candidates. Further optimization may enhance their therapeutic efficacy.

Oxidovanadium(IV) Porphyrin-Imidazole Complex-Catalyzed One-Pot, Three-Component Green Synthesis of Biologically Active Pyrano[2,3-d]pyrimidine and 4H-Chromene Heterocycles.

A β-functionalized porphyrin ligand {H2TPP(Phen)}, has been synthesized and subsequently employed as a dibasic tetradentate ligand in synthesizing its vanadyl complex 2-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)-5,10,15,20-tetraphenylporphyrinatooxido-vanadium(IV)[VIVOTPP(Phen)] (1). Comprehensive characterization of the ligand {H2TPP(Phen)} and its vanadyl(IV) complex (1) was achieved through various analytical and spectroscopic techniques, including NMR, ultraviolet-visible (UV-vis), EPR, and MALDI-TOF mass spectrometry and elemental analysis. Electrochemical studies indicated that the free base porphyrin {H2TPP(Phen)} tends to four successive reduction peaks and two oxidation peaks observed in cyclic voltammetry. In contrast, the metalated complex [VIVOTPP(Phen)] displayed two successive reversible reductions and two oxidation peaks. The synthesized vanadyl(IV)-porphyrin complex (1) was further employed as an efficient and reusable catalyst in an environmentally friendly, one-pot, three-component synthesis of biologically and clinically relevant pyrano[2,3-d]pyrimidine (Ca-Ch, Da-Dg) and 4H-chromene (Ga-Gj, Ha-Hj) heterocycles. Based on the current literature regarding one-pot, multicomponent reactions, two distinct and plausible mechanistic pathways are postulated for these transformations. A detailed mechanistic investigation, including the isolation of intermediates and stepwise reaction analysis, revealed that the type of 1,3-dicarbonyl compound used is pivotal in determining the operative mechanistic pathway in these reactions. The current catalytic protocol developed for the synthesis of pyrano[2,3-d]pyrimidine and 4H-chromene heterocycles presents several advantages over existing methodologies, including the use of an eco-friendly solvent (ethanol), high product yields (up to 97%), shorter reaction time scale (30 min), high turnover frequency (TOF) values (up to 14.7 min-1), and excellent catalyst reusability over five catalytic cycles.

Carbon Nanotubes Coupled Bipolar Covalent Organic Frameworks With Nitrogen-Enriched Redox-Active Sites for High-Performance Lithium-Organic Batteries.

Covalent organic frameworks (COFs) are frequently explored as attractive electrode materials for next-generation sustainable lithium-ion batteries. Unfortunately, such metal-free electrode materials suffer from low practical capacities and poor rate capabilities, due to low intrinsic conductivity, limited redox-active sites, and insufficient electrochemical utilization. Herein, integrating conductive carbon nanotubes (CNTs) with bipolar-type COFs enriched by multi-electron redox-active sites is rationally crafted by in situ Schiffbase condensation to fabricate robust core-shell hierarchical heterostructures (CNT@COF). Remarkably, the as-fabricated CNT@COF cathode delivers a large reversible capacity (253.1 mAh g-1 at 0.2 A g-1), high rate capability (161.6mA h g-1 at 5 A g-1), and excellent cycling stability (retaining 76.6% of initial capacity at 5 A g-1 over 1000 cycles), because of the fast ion/electron transport and high utilization of active groups. Accordingly, both spectroscopy techniques and theoretical calculations are employed to reveal the redox reaction mechanisms of COF moieties and the reversible conversion of bipolar-type nitrogen-containing active centers(imine, triazine, and triphenylamine) against with PF6 -/Li+ is rationalized clearly. This work crafts an unusual strategy to address common issues for organic polymer electrodes by macromolecular engineering to unlock the barrier of high-capacity and high-rate storage in powerful batteries.

Deep-Learning-Assisted Raman Spectral Analysis for Accurate Differentiation of Highly Structurally Similar CA Series Synthetic Cannabinoids.

Precise discrimination of the crucial substances, e.g., synthetic cannabinoids (SCs) that are composed of low-active chemical groups and structurally similar to each other with tiny differences, is a pressing need and of great significance for safeguarding public security and human health. The structure-relevant vibrational spectroscopic techniques, e.g., Raman spectroscopy, could reflect structural fingerprint information on the target; however, the algorithm-assisted phrasing is inevitable. This work achieved the accurate identification of CA series SCs by proposing an attention mechanism involving a CNN algorithm to phrase the Raman data. Specifically, these SCs have only one different chemical group compared to each other, the attention mechanism was introduced to intensify the computation on their structural difference from the massive data, realizing the accurate discrimination. Furthermore, how the spectral peaks corresponded to the specific structure was revealed, which plays a decisive role for the algorithm to distinguish these substances, and provides an instructive reference for differentiating other SCs based on Raman spectra. Hence, this work provides a research paradigm for applying the advanced CNN algorithm-aided Raman spectral analysis to sub-differentiate the substances, strengthening the understanding of spectral information from the sub-molecular level and propelling the integration of interdisciplinary areas.

Investigation of the coordination chemistry, biomolecular interactions and cytotoxicity of heterocyclic carboxamide manganese(II) complexes

Reactions of ligands 5‐methyl‐N‐(quinolin‐8‐yl)pyrazine‐2‐carboxamide (L1), N‐( N‐(pyridin‐2‐ylmethyl)pyrazine‐2‐carboxamide (L2), N‐(quinolin‐8‐yl)picolinamide (L3), N‐(quinolin‐8‐yl)quinoline‐2‐carboxamide (L4) with the MnCl2.4H2O salt afforded the respective manganese complexes [Mn(L1)(CH3OH)2Cl] (Mn1), [Mn(L2)2] (Mn2) [Mn(L3)2] (Mn3) and [Mn2(L4)2(CH3OH)2Cl2] (Mn4) in moderate yields. Solid state structures reveal complexes Mn1 and Mn2 as mononuclear species, while complex Mn4 is dinuclear. The partition coefficients of all the complexes indicated positive values, reflecting their lipophilicity. The interactions with calf thymus DNA (CT‐DNA) and bovine serum albumin (BSA) were investigated by spectroscopic techniques. The binding parameters of complexes Mn1‐Mn4 showed interactions with DNA, primarily through intercalative binding, reversible interactions with BSA through a static mode. The in vitro cytotoxicity studies of complexes Mn1‐Mn4 against human colorectal adenocarcinoma (Caco‐2) and breast cancer (MCF‐7) cancer cells revealed that Mn1 and Mn3 were inactive, while Mn2 (IC50 = 76.18 μM) and Mn4 (IC50 = 38.03 μM) showed lower cytotoxicity than cisplatin (IC50 = 16.07 μM) against Caco‐2 cell line.

Force Volume Atomic Force Microscopy-Infrared for Simultaneous Nanoscale Chemical and Mechanical Spectromicroscopy.

Photothermal atomic force microscopy-infrared (AFM-IR) combines the nanoscale spatial resolution of AFM with the chemical identification capability of infrared spectroscopy and has thrived in various applications. Currently executed in three major AFM modes (contact, tapping, and peak force tapping) we introduce a fourth variant built upon force volume mode comprising a defined engage, hold, and retract segment in each pixel. IR laser pulsing at a probe resonance frequency during the constant-force hold segment duplicates the resonance-enhanced AFM-IR detection principle of contact mode. However, force volume AFM-IR removes the lateral forces that cause tip wear and sample damage while adding the spatial resolution of tapping AFM-IR. As demonstrated on different materials, this imaging and spectroscopy technique integrates monolayer sensitivity, sub-10 nm spatial chemical resolution, simultaneous nanomechanical property sensing, and precise force control. The ability to sweep the infrared laser repetition rate in each pixel provides additional, rich information in the form of contact resonance curves, while compensating for mechanically induced probe resonance shifts in an alternative to conventional phase-locked loop based frequency tracking. Such sweeps inherently consider the Q-factor (i.e., mechanical damping) in the AFM-IR response, a little investigated aspect. Furthermore, the probing depth can be varied by selecting different resonances recorded within a single broad frequency sweep. Switching to the surface sensitive AFM-IR detection scheme during the hold segment additionally limits the probing depth. These qualities should position force volume AFM-IR as a valuable addition to established AFM-IR modes.

Synthesis, Characterization, and Reactivity of Aminotroponiminate-Based Difluoroboranes: A Pathway toward Bore(boro)nium Cations.

Aminotroponiminates (ATIs), a well-known monoanionic bidentate ligand, display a wide range of coordination chemistry. To exploit their electronic and steric factors in achieving boron cations, a series of symmetrical, unsymmetrical, and bis(ATI) borane complexes [(C7H5)(NiPr)2BF2] (3a), [(C7H5)(NtBu)2BF2] (3b), [(C7H5)(NiBu)2BF2] (3c), [(C7H5)(NiBu)(NtBu)BF2] (3d), and [(C7H5)(NiPr)(NCH2)BF2]2 (3e) were synthesized in this work. All the ATI borane complexes are highly blue luminescent in the solution, and their fluorescence decay time was recorded in DCM. The observed decay time range was found to exist between 1.7 and 2.8 ns. Complexes 3a and 3b when treated with trimethylsilyl triflate (TMS-OTf) enabled the isolation of tricoordinated borenium cations [(C7H5)(NiPr)2BOH]+ (4a) and [(C7H5)(NtBu)2BOH]+ (4b), respectively. Interestingly, the reaction of bis(ATI) borane 3e and TMS-OTf resulted in a boron dication 4e in which the borenium and boronium cations are bridged via an oxygen atom in a seven-membered ring scaffold. All of the ATI boranes and cations were well characterized by various spectroscopic techniques in solution and X-ray structure diffraction analysis in the solid state. Further, theoretical calculations using density functional theory (DFT) were conducted to understand the electronic structure and bonding scenario of these complexes.

Illuminating extracellular nanovesicles through the spectroscopic lens: a mini review of cutting-edge insights and emerging applications

Extracellular vesicles (EVs) are cell-derived particles that facilitate intercellular communication by carrying bioactive molecules like proteins and RNA, impacting both health and disease. Herein, the EVs' significance in physiological and pathological processes is reviewed, emphasising their potential as biomarkers for diseases including for instance, cancer, neurodegenerative disorders and cardiovascular conditions. The principles and applications of Raman spectroscopy (RS) - a powerful tool offering detailed molecular insights into EVs, are further examined. The non-destructive nature of this spectroscopic technique renders it invaluable for studying the molecular composition, purity and concentration of EVs. When EVs are isolated from accessible biofluids such as blood, urine or saliva, the overall process remains minimally invasive, enhancing its clinical applicability. The review highlights Raman spectroscopy’s role in identifying disease-related EVs, distinguishing subpopulations and enhancing our understanding of EVs in disease mechanisms and therapeutic applications.

Pressure Dependent Excited State Dynamics Behavior in CzCNDSB

Abstract High-pressure can change the properties of matter and modulate the excited state relaxation behavior of materials without intervention. In this study, high-pressure was combined with steady state absorption and fluorescence spectroscopy, transient spectroscopy techniques to investigate the effect of pressure on the optical properties of the stimuli-responsive material CzCNDSB. With increasing pressure, the steady state absorption and fluorescence peaks of CzCNDSB crystals are red-shifted and well reversible. At the same time, the molecules become closer to each other with the increase of pressure, which induce the multiplet self-trapped state increase in number and energy as well as the local excited states decrease in energy. The steady state and transient state results provide information on electronic energy levels, excited state dynamics, etc. for the study of CzCNDSB materials, which show strong dependence on pressure. These findings could show more favorable advantages in practical applications such as photodetectors and solar energy etc..

Nuclear radii from first principles

With the combination of nuclear interactions from chiral effective field theory and various many-body techniques, one can perform systematically improvable ab initio calculations. As the improvable framework enables us to quantify the uncertainty, it is particularly useful to make a prediction for which performing experiments is difficult or even impossible. Neutron skin thickness, the difference between neutron and proton distribution radii, is a key quantity related to the properties of infinite nuclear matter. Since neutrons do not have a net electric charge, the neutron-distribution radius is difficult to measure, preventing precise measurement of neutron skin thickness. On the other hand, recent developments in laser spectroscopy techniques can provide detailed information on the charge distribution and opportunities for detailed comparisons to theoretical results. Testing the theoretical frameworks with the measurable charge radii should be a step toward predicting other quantities, such as neutron skin thickness. This contribution reviews recent advances in nuclear radii and neutron skin from ab initio calculations.

Famous but unknown – structural characterization of the Ru-MACHO catalyst

Abstract In this work, we present the determination of the crystal structure of the wildly used transition metal complex known as ruthenium macho. The crystal structure of the selectively formed product of the reaction between the titled complex and hydrochloric acid chloroform is also evaluated. The structures determined in this work are compared and evaluated with various spectroscopic techniques.

Discovery of Antibacterial Azaphilone Hybrid Metabolites from Marine-Derived Aspergillus terreus PPS1.

Three novel azaphilone hybrids (1-3) with two types of structural units, along with four known compounds (4-7), were obtained from the marine sediment-derived fungus Aspergillus terreus PPS1. Asperbenzophilone A (1) features an unprecedented 6/6/6/6 ring system containing a hemiketal group. Butyropyranones I and II (2 and 3) are equipped with an azaphilone fragment preasperpyranone and a butyrolactone, which are connected through ether bonds. Comprehensive spectroscopic techniques, ECD calculations, and deduction of biosynthetic pathways were used to confirm the planar structures and absolute configurations of the new compounds. Compound 2 displayed significant anti-MRSA activity. Additionally, compound 2 exhibited moderate cytotoxic activity on human tumor cell lines 786-O, 5637, MCF-7, A-673, and 293T and medium inhibitory activity against the SARS-CoV-2 main protease (Mpro/3CLpro).

Small Polaron-Induced Ultrafast Ferroelectric Restoration in BiFeO3

In this report, we apply a suite of ultrafast spectroscopic techniques and advanced calculations to reveal the interplay between electronic and lattice degrees of freedom in ferroelectric BiFeO3. Using transient sum frequency generation spectroscopy, which is sensitive to electronic polarizations, we observe a transient electronic dipole reduction upon optical excitation which recovers at 0.5 and 10 ps timescale. The time-dependent density functional theory calculation reveals that both ligand-metal charge transfer and local excitation transition occurred upon photo excitation. To reveal the nature of electronic dipole restoration, we employ transient extreme ultraviolet (EUV) spectroscopy—an element-specific ultrafast technique that follows charge dynamics of Bi, Fe, and O altogether. The transient EUV dynamics observed both ultrafast free charge carrier relaxation to excitons, as well as polaron formation. However, a timescale comparison suggests that only the polaron formation is responsible for the 0.5 ps electronic dipole restoration, whereas the faster electronic relaxation does not contribute to the ferroelectric property changes. Multireference configuration interaction calculation further corroborates this result by showing both Fe and Bi atoms shift from the ground state equilibrium—leading to the polaron formation. Our result disentangles the multidegrees of freedom in ultrafast ferroelectric modulation and identifies the pivotal motion—a local polaron formation—for the fast ferroelectric recovery. It provides crucial insights on the specific lattice distortion that could modulate properties or phase transitions of condensed matter materials. Published by the American Physical Society 2025

Design and Characterizations of Essential Metal (II)-Amino Acid : L-Arginine & L- Alanine containing Polyphosphonitrile Derivatives

Over the past decade, inorganic polymers, particularly polyphosphazenes, have garnered significant attention in materials science due to their unique structural versatility and tuneable properties. Polyorganophosphazenes, with the general formula [NPR2], offer a broad range of physical and chemical characteristics, largely determined by the nature of their side groups (R), which can include Amino, Alkoxy, Aryloxy, Alkyl, or Aryl functionalities. In this study, we report the synthesis and characterization of a novel class of inorganic polymeric derivatives Metal (II)-amino acid-substituted polyphosphonitriles. These derivatives were prepared using amino acids (L-arginine and L-alanine) and side groups containing sodium, ethoxy, and phenoxy moieties. The central Metal(II) ions—Zn(II), Cu(II), Mg(II), Ca(II), and Fe(II)—are essential metals with known biological and catalytic relevance. The successful incorporation of these components was achieved through controlled polymerization and substitution reactions, resulting in structurally diverse and functionally promising materials. The synthesized polymers were characterized by their physical properties, including colour, conductivity, pH, melting point, dipole moment, and dielectric behaviour. Spectroscopic techniques such as Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) were employed to confirm the structural features of the new materials. This study introduces a promising new class of inorganic-organic hybrid polymers with potential applications in areas such as Biomedicine, Environmental Remediation, Agricultural area and Advanced Material Engineering.

Nifuroxazide and 4-Hydroxybenzhydrazone Derivatives as New Antiparasitic (Trypanosoma cruzi and Leishmania mexicana) and Anti-Mycobacterium tuberculosis Agents

Background/Objectives: Nifuroxazide (Nfz) is a drug that has been used as a scaffold for designing antimicrobial and antiparasitic agents. This study aimed to synthesize and evaluate in vitro of Nfz and twenty-five 4-hydroxybenzhydrazone derivatives as potential anti-Trypanosoma cruzi, anti-Leishmania mexicana, and anti-Mycobacterium tuberculosis agents. Methods: The compounds were synthesized by condensing 4-hydroxybenzhydrazide with appropriate aldehydes in acidic conditions and structurally confirmed by spectroscopic techniques. All compounds were evaluated in vitro against T. cruzi strains (NINOA and A1), L. mexicana (M379 and FCQEPS strains), and M. tuberculosis (H37Rv strain), followed by enzymatic assays against T. cruzi cysteine proteases. Results: Compound Nfz-24 (IC50 = 6.8 μM) had better trypanocidal activity than the reference drugs benznidazole (IC50 > 30 μM) and nifurtimox (IC50 > 7 μM) against the NINOA strain, and Nfz-8 (IC50 = 7.2 μM) was the compound most active against the A1 strain with a high inhibition of T. cruzi cysteine proteases (IC50 = 4.6 μM) and low cytotoxic effects (CC50 >100 μM). On the other hand, compound Nfz-5 (IC50 = 5.2 μM) had a 25-fold better leishmanicidal effect than glucantime (IC50 > 125 μM) against the L. mexicana M379 strain, and compound Nfz-13 had the best leishmanicidal effects (IC50 = 10.2 μM) against the FCQEPS strain. Finally, Nfz, Nfz-1, and Nfz-2 had minimum inhibitory concentration (MIC) values of 12.3, 5.1, and 18.8 μg/mL against M. tuberculosis, respectively. Conclusions: In summary, these results suggest that the compounds Nfz-1, Nfz-2, Nfz-5, Nfz-8, Nfz-10, Nfz-15, Nfz-24, and Nfz-25 are candidates for further studies to develop new and more potent anti-T. cruzi, anti-leishmaniasis, and anti-M. tuberculosis agents.

White Light Emission from Luminescent Lanthanide Molecular Complex/Terbium Doped Graphene Quantum Dots/PMMA Composites.

Construction of multicolor emissive PMMA composite films are reported using luminescent lanthanide Schiff-Base complexes and Terbium doped Graphene Quantum dots (GQD@Tb) for white light generation. Terbium-doped green emissive Graphene Quantum Dots are synthesized hydrothermally using ortho-phenyldiammine (OPDA), Triethylamine and Tb(NO3)3.6H2O and is thoroughly characterized by microscopic and spectroscopic techniques. Isostructural lanthanides (III) complexes [DyIII 2(L)2(NO3)2(dmf)2] (1), and [SmIII 2(L)2(NO3)2(dmf)2] (2) are isolated from an organic Schiff base ligand, H2L, ligand is prepared by 1:1 condensation of salicylaldehyde and 2-(2-Aminoethoxy)ethanol, and are characterized. The photoluminescent data analysis reveals green emission of GQD@Tb, pure blue emissive DyIIIL and red emission of SmIIIL. Additionally, intensified ligand emission attests for the blue emitter-DyIIIL complex while the "antenna effect" is witnessed for red fluorophore SmIIIL. Co-doping of metal complexes and GQD@Tb into the Poly(methyl methylacrylate) [PMMA] polymer improves luminescence intensity due to inhibition of aggregation-induced quenching. By conscientious combination of red-SmIIIL with green-GQD@Tb in a specified concentration, distinct white light is accomplished for the first time with Commission Internationale de I'Éclairage (CIE) values of 0.29, 0.32, very close to the ideal white emitter. The newly developed nano and molecular complex composite of GQD@Tb and SmIIIL-PMMA films are transparent and highly desired materials in optoelectronics, microscopy, and sensing.

Extended thermal admittance spectroscopy for the investigation of composition-dependent meta-stability behaviours in wide-gap (Ag,Cu)(In,Ga)Se2 solar cells

Abstract In this contribution, voltage- and temperature-dependent admittance spectroscopy is used in concert with other electrical characterisation techniques to gain insight into composition-dependent variations in the meta-stable behaviour of the (Ag,Cu)(In,Ga)Se2 system. The extended thermal admittance spectroscopy techniques are powerful tools for the evaluation of meta-stabilities, providing multiple approaches for the determination of the likely origins of observed capacitance features. These capabilities, which enable cross-referencing and verification of capacitance feature labelling, enhance the confidence in conclusions deduced from the often ambiguous and complex admittance spectroscopy methods. Our results indicate that high levels of Ag alloying lead to charge transport barriers active at low temperatures (below 220K) and, for the off-stoichiometric case, a shallow acceptor state 150meV above the valence band edge. Lightsoaking-induced increases in the activation energy and, consequently, decreases in the occupation of this acceptor state closely reflect the decrease in net doping concentration induced by lightsoaking in the off-stoichiometric high-Ag device. The presence of the acceptor state also correlates with the large difference in net doping concentration between the close- and off-stoichiometric high-Ag devices. For moderate Ag-alloying and Ag-free devices, it is shown that off-stoichiometry introduces secondary capacitance features, alongside a common feature observed in both close- and off-stoichiometric devices. These features are determined to originate from a combination of deep defects and charge transport barriers.

Synthesis, Electronic, Dynamic Optical and Adsorption (Monte Carlo and Molecular Dynamics) Properties of Cadmium Picolinate Coordination Polymer-2 (Cp-2)

The cadmium picolinate coordination polymer (CP-2) was synthesized through the reaction of picolinic acid with cadmium acetate dihydrate. CP-2 was characterized using spectroscopic techniques, elemental analysis and powder X-ray diffraction. Variations in melting point, infrared and ultraviolet-visible spectra, along with the results of elemental analysis and powder X-ray diffraction, strongly support the successful formation of the cadmium-picolinic acid CP. The molecular, electronic, optical and adsorption properties of the CP-2 were studied using density functional theory (DFT), time-dependent DFT (TD-DFT), molecular dynamics (MD) and Monte Carlo (MC) simulations. The DFT calculations with B3LYP/LANL2DZ/6-311[Formula: see text]G(d,p) method provided insights into the molecular reactivity and electronic structure, revealing key reactivity parameters (such as frontier orbital energies, energy gap, electronegativity and electrophilicity) and charge distribution within the CP. Dynamic optical calculation was conducted using coupled perturbed Hartree-Fock formalism with DFT/B3LYP/LANL2DZ/6-311[Formula: see text]G(d,p) method. TD-DFT calculations elucidated the electronic absorption properties of the CP, with a low-energy transition at 341 nm. The static [[Formula: see text](0;0,0); [Formula: see text](0;0,0,0)] and dynamic [EOPE: [Formula: see text];[Formula: see text],0)]); SHG: [Formula: see text]2[Formula: see text];[Formula: see text],[Formula: see text]]; EOKE: [Formula: see text];[Formula: see text],0,0); DCSHG: [Formula: see text]2[Formula: see text];[Formula: see text],[Formula: see text],0)] nonlinear optical properties ([Formula: see text] 0.042823 au) displayed large hyperpolarizabilities, suggesting potential applications in SHG and THG. The third-order NLO properties were greater than those of the KH2PO4 (standard). MC simulations explored the adsorption of selected gases (CO2, CH4, H2S, HCHO, NH3) and 2,4-dinitrotoluene (DNT) on the CP-2, revealing strong binding interactions, particularly with H2S. MD simulations further confirmed the stability of the adsorbates on the CP-2 framework.