Unique Spectroscopic Features Research Articles

Coupled Experimental-Theoretical Characterization of a Carbon Electrode in Vanadium Redox Flow Batteries using X-ray Absorption Spectroscopy.

Vanadium redox flow batteries (VRFBs) have emerged as promising solutions for stationary grid energy storage due to their high efficiency, scalability, safety, near room-temperature operation conditions, and the ability to independently size power and energy capacities. The performance of VRFBs heavily relies on the redox couple reactions of V2+/V3+ and VO2+/VO2+ on carbon electrodes. Therefore, a thorough understanding of the surface functionality of carbon electrodes and their propensity for degradation during electrochemical cycles is crucial for designing VRFBs with extended lifespans. In this study, we present a coupled experimental-theoretical approach based on carbon K edge X-ray absorption spectroscopy (XAS) to characterize carbon electrodes prepared under different conditions and identify relevant functional groups that contribute to unique spectroscopic features. Atomic models were created to represent functional groups, such as hydroxyl, carboxyl, methyl, and aldehyde, bonded to carbon atoms in either sp2 or sp3 environments. The interactions between functionalized carbon and various solvated vanadium complexes were modeled using density functional theory. A library of carbon K-edge XAS spectra was generated for distinct carbon atoms in different functional groups, both before and after interacting with solvated vanadium complexes. We demonstrate how these simulated spectra can be used to deconvolve ex situ experimental spectra measured from carbon electrodes and to track changes in the electrode composition following immersion in different electrolytes or extended cycling within a functional VRFB. By doing so, we identify the active species present on the carbon electrodes, which play a crucial role in determining their electrochemical performance.

A Decomposition of the Atmospheric and Surface Contributions to the Outgoing Longwave Radiation

AbstractThe outgoing longwave radiation (OLR), which consists of the thermal radiation from both the atmosphere and surface, is of critical importance to the Earth radiation energy budget. To understand the global OLR distribution, it is important to quantify the varying atmospheric and surface contributions. In this work, we present such a quantification using radiative transfer computations based on global reanalysis atmospheric data. By dissecting the OLR simulated following the radiative transfer equation, we quantitatively measure the layer‐wise atmospheric contributions to OLR and compare it to the surface contribution in different spectral bands. One focus of this study is on the OLR in the far‐infrared (FIR), for which new satellites are expected to provide unprecedented measurements. We find that around 45% of the global mean OLR is radiated in the FIR and in polar regions the FIR contribution can increase to 60%. Our vertical decomposition of OLR discloses that although the atmospheric contribution generally surpasses the surface contribution, the enhanced FIR contribution in the polar regions mainly results from a relatively stronger surface (as opposed to atmospheric) contribution. This is allowed by the opening of the atmospheric window in the FIR in these extremely dry regions. Our analysis also reveals that the tropopause layer makes a minimum contribution to the OLR, which may be a unique spectroscopic feature of the Earth atmosphere. Clouds are found to reduce the atmospheric contribution in the FIR while enhancing it in the mid‐infrared.

SH-It happens: S-H bonds as intrinsic 2D-IR labels in proteins.

Cysteine S-H bonds have a spectroscopically convenient stretching frequency of ∼2550cm-1. However, their cross section is low, and the band can be strongly broadened in heterogeneous environments, making detection very challenging. With two-dimensional infrared (2D-IR) setups achieving ever higher sensitivities in recent years, systematic use of the weak cysteine sulfhydryls (Cys-SHs) absorption band is now within reach, even at low millimolar protein concentrations. Here, we demonstrate the capabilities of Cys-SH as an intrinsic 2D-IR label in pyruvate oxidase from E. coli, an enzyme with ten cysteines in its native sequence. 1D-IR measurements on the wild-type and individual cysteine knock-out variants show that two such residues have especially narrow SH signatures, caused by their intrahelical hydrogen bonding. 2D-IR analysis of these bands reveals an extraordinarily high anharmonicity (∼110cm-1) and a long vibrational lifetime (∼4ps). This allows monitoring spectral diffusion via center line slope analysis for up to 10 ps-separately for both the ground and excited states. The unique spectroscopic features and its ease of introduction make Cys-SH a useful IR spectroscopic label.

(Digital Presentation) Electro-Oxidative Trimerization of Catechol to Hexahydroxytriphenylene Using a Flow Microreactor

Due to their unique spectroscopic and geometric features, discotic liquid crystals (DLCs) have a variety of possible applications, including optical compensation films for liquid crystal displays, organic semiconductors for electronic devices, organic light-emitting diodes (OLEDs), and organic photovoltaic cells (OPVs).The most basic molecular structure of DLC is that of a triphenylene core surrounded by alkoxy and acyloxy groups. Even today, triphenylene with 2,3,6,7,10,11-hexaalkoxy and acyloxy groups is considered to be a common structural motif of DLC, and is undergoing rapid development. Until the 1990s, many studies had been reported on the synthesis of these hexasubstituted triphenylenes by trimerization of 1,2-disubstituted benzenes, but these protocols were not practical industrially due to the limitation of substituents, lack of reproducibility, the need for strict temperature control at -80°C, and poor solubility of reagents. Hence, today, the introduction of alkyl or acyl groups into 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) has become a common synthetic strategy for hexasubstituted triphenylene. Therefore, HHTP is an important starting material for the synthesis of various types of hexasubstituted triphenylene.HHTP was conventionally synthesized by oxidative trimerization of 1,2-dimethoxybenzene followed by demethylation of the resulting hexamethoxytriphenylene. However, this method required the use of at least a stoichiometric amount of sulfuric acid, which generated a large amount of waste acid. Therefore, the development of more efficient methods, such as trimerization of 1,2-dihydroxybenzene (catechol) to HHTP, has been actively studied in recent years. Kobori et al. synthesized HHTP in 70-76% yield by oxidative trimerization of catechol using FeCl3 as an oxidant. However, the HHTP product was contaminated with Fe impurities, which was undesirable for the application of DLC in the display and semiconductor industries. Furthermore, this protocol includes a reduction step of peroxidized HHTP (quinone), which accounts for 40-60% of the total HHTP yields. Some other protocols do not use metal reagents, but they use 60-80 wt% H2SO4 aq., which result in a large amount of waste acid.On the other hand, we have recently developed an efficient method for aromatic C,C-coupling reactions by electrochemical oxidation in a flow microreactor. In this synthetic method, peroxidation of the products can be avoided by controlling the residence time in the reactor. In addition, electrochemical oxidation can be carried out without the use of oxidants or catalysts. Thus, this synthetic method has many features to overcome the drawbacks of conventional methods.In this study, we have successfully carried out the electro-oxidative trimerization of catechol in a flow microreactor to synthesize HHTP efficiently without the need for metallic reagents and reduction procedures.As a result, HHTP was obtained in 20% yield using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a solvent. The results showed that the radical cations of catechol, which were generated on the anode surface, proceeds C,C-coupling in HFIP. On the other hand, the yield decreased to 4% or 0% when HFIP/H2O mixed solvents were used. DFT calculation suggested that the proton dissociation equilibrium of catechol intermediate greatly affects the reaction mechanism. We calculated the pK a values of catechol intermediate in each HFIP/H2O solvent composition, and discussed the effect of H2O contamination on the HHTP yield. Figure 1

Mechanochemical synthesis of six Cu(II) complexes with selected thiols, their physicochemical characterization and interaction with DNA

• Some Cu(II)-thiolates have been synthesized in the solid state. • The complexes are stable and exhibit spectroscopic features similar to those in the Type 1 site. • Cu(II)-mercaptosuccinic acid and Cu(II)- n -acetylcysteine cause extensive degradation, whereas Cu(II)-penicillamine and Cu(II)-glutathione significantly degraded the DNA. • Cu(II)-cysteine appears to form an adduct with the DNA. • Docking of Cu(II)-cysteine with thioredoxine reductase suggests that the complex has the potential to inhibit the activity of the enzyme. Cysteine together with histidine (His 2 Cys) has been identified as one of the ligands in Type 1 copper protein active sites, and Cu-S(Cys) interaction determines their unique spectroscopic features. This work reports the synthesis of model Cu(II)-thiolates, which could mimic the Type 1 sites. The Cu(II)-complexes with l -cysteine, n -acetylcysteine, l -glutathione, l -penicillamine, mercaptosuccinic acid and dl -dithiothreitol were synthesized by solvent-free mechanochemical methods. The complexes were found to be of the ML 2 type as revealed by solid-state analytical techniques including FT-IR (ATR) spectroscopy, Raman spectroscopy, electronic absorption spectroscopy (diffuse reflectance), powder X-ray diffraction and desorption electrospray ionization mass spectrometry. These compounds are difficult, in some cases impossible, to isolate from solution because of rapid oxidation of thiols to disulfides and reduction of Cu(II) to Cu(I) or Cu(0). However, in the solid state these complexes were found to be highly stable and exhibited spectroscopic features similar to those in the Type 1 site. Interaction of the complexes with genomic DNA isolated from human blood was studied by electrophoresis, which showed that Cu(II)-mercaptosuccinic acid and Cu(II)- n -acetylcysteine caused extensive degradation, whereas Cu(II)-penicillamine amd Cu(II)-glutathione significantly degraded the DNA. Cu(II)-cysteine appears to form DNA adducts. Docking of Cu(II)-cysteine with thioredoxine reductase suggests that the complex has the potential to inhibit the activity of the enzyme.

Discovery of Environment-Sensitive Fluorescent Ligands of β-Adrenergic Receptors for Cell Imaging and NanoBRET Assay.

By fusing several environment-sensitive fluorophores to the pharmacophore mirabegron, a series of new fluorescent ligands for β-adrenergic receptors (β-ARs) were produced with a turn-on mechanism and high binding affinity to β-ARs efficiently. Compound L5 with the pyridinium moiety possessed the most favorable combination of properties after systematic comparison and optimization, including high affinity and acceptable cytotoxicity, remarkable fluorescence enhancement (up to 30-fold) upon binding with β-ARs, and feasible visualizing ability of β-ARs in living cells under no-wash conditions. Furthermore, a NanoLuc-based bioluminescence resonance energy transfer (NanoBRET) binding assay based on compound L5 was developed and may be used in high-throughput screening (HTS) in the drug discovery of β-ARs due to its unique fluorescence spectroscopic features. Overall, as the first environment-sensitive fluorescent ligand, molecule L5 could be a useful tool for understanding the pharmacology of β-ARs.

Synthesis of a Series of Tropone-Fused Porphyrinoids.

A series of tropone-fused porphyrinoids with unique spectroscopic features has been prepared. A dimethyl tropone-fused pyrrole was reacted with lead tetraacetate to give a bis(acetoxymethyl) derivative that condensed with an α-unsubstituted pyrrole tert-butyl ester to form a tripyrrane intermediate. Cleavage of the tert-butyl ester protective groups, followed by condensation with a series of aromatic dialdehydes and oxidation with DDQ, afforded the tropone-fused porphyrinoid systems. Reactions with pyrrole, furan, thiophene, and selenophene dialdehydes gave tropone-fused porphyrins and related heteroporphyrins. In addition, indene, 4-hydroxybenzene, and 3-hydroxypyridine dicarbaldehydes generated examples of carba-, oxybenzi-, and oxypyriporphyrins. The electronic absorption spectra of the tropone-fused porphyrinoids were greatly altered, showing shifts to longer wavelengths and the appearance of strong Q bands between 600 and 800 nm. The proton nuclear magnetic resonance spectra were also very unusual, as the internal protons were strongly shifted upfield, in some cases giving rise to resonances that approached -10 ppm. However, the external protons showed reduced downfield shifts compared to porphyrinoids that do not have tropone ring fusion. The profound changes observed for these macrocycles demonstrate that the introduction of fused tropone units, together with other structural changes such as core modification, can provide the means by which porphyrinoids with unique spectroscopic properties can be accessed.

Spiers Memorial Lecture: activating metal sites for biological electron transfer.

Metal sites in biology often exhibit unique spectroscopic features that reflect novel geometric and electronic structures imposed by the protein that are key to reactivity. The blue copper active site involved in long range, rapid biological electron transfer is a classic example. This review presents an overview of both traditional and synchrotron based spectroscopic methods and their coupling to electronic structure calculations to understand the unique features of the blue copper active site, their contributions to function and the role of the protein in determining the geometric and electronic structure of the active site (called the "entatic state"). The relation of this active site to other biological electron transfer sites is further developed. In particular, ultrafast XFEL spectroscopy is used to evaluate the methionine-S-Fe bond in cytochrome c, and its entatic control by the protein in determining function (electron transfer vs. apoptosis).

Measurement report: Molecular composition, optical properties, and radiative effects of water-soluble organic carbon in snowpack samples from northern Xinjiang, China

Abstract. Water-soluble organic carbon (WSOC) in the cryosphere has an important impact on the biogeochemistry cycling and snow–ice surface energy balance through changes in the surface albedo. This work reports on the chemical characterization of WSOC in 28 representative snowpack samples collected across a regional area of northern Xinjiang, northwestern China. We employed multimodal analytical chemistry techniques to investigate both bulk and molecular-level composition of WSOC and its optical properties, informing the follow-up radiative forcing (RF) modeling estimates. Based on the geographic differences and proximity of emission sources, the snowpack collection sites were grouped as urban/industrial (U), rural/remote (R), and soil-influenced (S) sites, for which average WSOC total mass loadings were measured as 1968 ± 953 ng g−1 (U), 885 ± 328 ng g−1 (R), and 2082 ± 1438 ng g−1 (S), respectively. The S sites showed the higher mass absorption coefficients at 365 nm (MAC365) of 0.94 ± 0.31 m2 g−1 compared to those of U and R sites (0.39 ± 0.11 m2 g−1 and 0.38 ± 0.12 m2 g−1, respectively). Bulk composition of WSOC in the snowpack samples and its basic source apportionment was inferred from the excitation–emission matrices and the parallel factor analysis featuring relative contributions of one protein-like (PRLIS) and two humic-like (HULIS-1 and HULIS-2) components with ratios specific to each of the S, U, and R sites. Additionally, a sample from site 120 showed unique pollutant concentrations and spectroscopic features remarkably different from all other U, R, and S samples. Molecular-level characterization of WSOC using high-resolution mass spectrometry (HRMS) provided further insights into chemical differences among four types of samples (U, R, S, and 120). Specifically, many reduced-sulfur-containing species with high degrees of unsaturation and aromaticity were uniquely identified in U samples, suggesting an anthropogenic source. Aliphatic/protein-like species showed the highest contribution in R samples, indicating their biogenic origin. The WSOC components from S samples showed high oxygenation and saturation levels. A few unique CHON and CHONS compounds with high unsaturation degree and molecular weight were detected in the 120 sample, which might be anthraquinone derivatives from plant debris. Modeling of the WSOC-induced RF values showed warming effects of 0.04 to 0.59 W m−2 among different groups of sites, which contribute up to 16 % of that caused by black carbon (BC), demonstrating the important influences of WSOC on the snow energy budget.

Anodic Trimerization of Catechol to Hexahydroxytriphenylene Using a Flow Microreactor

The unique spectroscopic and geometric features of discotic liquid crystals (DLCs) give rise to a variety of applications, for example, optical compensating films in the liquid crystal display industry, organic semiconductors in electronic devices, organic light-emitting diodes (OLEDs), organic photovoltaic solar cells (OPVs) and so on. The most basic molecular structure of DLCs consists of triphenylene core surrounded by alkoxy or acyloxy groups. Even today, 2,3,6,7,10,11-hexaalkoxy- and acyloxy-substituted triphenylenes are seen as a common structure motif of DLCs, and achieving rapid development. Until 1990s, many studies had been reported on the synthesis of these hexasubstituted triphenylenes by the trimerization of 1,2-disubstituted benzenes, however, those protocols were not practical for industrial use, because of the limited scope of substituents, lack of reproducibility, requirement of strict temperature control at -80℃, or poor solubility of the reagents. As a result of these difficulties, today’s common synthetic strategy for hexasubstituted triphenylenes is to introduce alkyl and acyl groups into 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP). Therefore, HHTP is an important starting material in the preparation of various types of hexasubstituted triphenylenes. HHTP was classically synthesized by the oxidative cyclotrimerization of 1,2-dimethoxybenzene followed by demethylation of resulting hexamethoxy-triphenylene. However, in the demethylation procedure, at least the stoichiometric amount of hydrohalic acid was used, and a large amount of waste acid was produced. Therefore, the development of more efficient method like a trimerization of 1,2-dihydroxybenzene (catechol) to HHTP has been studied vigorously in recent years. Kobori et al. synthesized HHTP by oxidative trimerization of catechol using FeCl3 as an oxidant in 70-76% yield. However, the contamination of Fe impurity into HHTP product is unfavorable in the application of DLCs to display and semiconductor industry. In addition, this protocol involves a reduction process of over-oxidized HHTP (quinones), which accounts for 40-60% of the total HHTP yield. Some other protocols do not use metal reagents, however, the use of 60-80wt% H2SO4 aq. results in the generation of an enormous amount of waste acid. On the other hand, recently, we have developed an efficient method for aromatic C,C-coupling reaction using electrochemical oxidation in a flow microreactor. Using this synthetic method, over-oxidation of the product can be avoidable by the control of residence time in the reactor. In addition, electrochemical oxidation was conducted without any oxidants or catalysts. Thus, this synthetic method possesses many characteristics designed to overcome the disadvantages of conventional methods. Under these backgrounds, in the present work, we have demonstrated the electro-oxidative trimerization of catechol in a flow microreactor in order to synthesize HHTP efficiently without the use of metal reagents nor reduction procedure. As a result, HHTP was obtained as a main product in the yield of 40-47% using 50-200mM trifluoromethanesulfonic acid solution in the mixed solvent of 70%(v/v) water and 30%(v/v) 2,3,6,7,10,11-hexafluoro-2-propanol(HFIP). The result indicates that C,C-coupling of catechol intermediate proceeded predominantly to produce HHTP, and this mechanism was supported by DFT calculation. Figure 1

Microviscosity and temperature sensors: The twists and turns of the photophysics of conjugated porphyrin dimers — a SPP/JPP Young Investigator Award paper

Conjugated porphyrin dimers have captured the imagination of scientists due to a set of unique spectroscopic features such as remarkable nonlinear-optical properties, high yields of singlet oxygen sensitization and the absorption and emission in the far-red region of the visible spectrum. Here we review a range of newly emerged applications of porphyrin dimers as sensors of their microenvironment such as viscosity and temperature. We discuss the sensing mechanism based on the known conformational flexibility of the dimer structure and describe possible applications of these unique sensors, from detecting viscosity increase during photoinduced cell death to structural responses of polymers and artificial lipid membranes, to temperature changes, and to mechanical deformation.

Flame structure of supercritical ethanol/water combustion in a co-flow air stream characterized by Raman chemical analysis

The thermochemical properties of the ethanol hydrothermal flame (30%-v ethanol-water solution), established in air co-flow under supercritical water conditions, are measured by a quantitative Raman diagnostic technique. The unique spectroscopic features of the chemical compounds are revealed to aid understanding of the fuel decomposition and oxidation process in supercritical phase. A point-wise fiber-optic probe is designed to resolve the needle-like thin flame and identify the spatial profiles – across the flame thickness and over the height of the visible flame – of the combustion species at different fuel/air ratios and airflow rates. An attempt is made to analyze the steep thermal gradients in the primary reaction zone near the fuel nozzle by estimating thermodynamic temperatures from the measured fluid density. The test cell was held at conditions above the critical point of water, at a nominal pressure of 25 MPa and a nominal temperature of 723 K (450 °C). The flames were over ventilated with an excess air:fuel ratio between two and five times stoichiometric. Depending upon the air:fuel ratio non-sooting blue flames or yellow sooting flames are observed. The results of the Raman diagnostic provide temperature and species profiles that will prove useful for validating numerical models using an idealized laboratory hydrothermal flame. The Raman diagnostic results are augmented with imaging from two orthogonal camera views: a backlit shadow-graphic image of the co-flow jet and a color image of the flame.

Shannon entropy as a predictor of avoided crossing in confined atoms

AbstractAvoided crossing is one of the unique spectroscopic features of a confined atomic system. Shannon information entropy of the ground state and some of the excited states of confined H atom as a predictor of avoided crossing is studied in this work. This is accomplished by varying the strength of the confinement and examining structure properties like ionization energy and Shannon information entropy. Along with the energy level repulsion at the avoided crossing, Shannon information entropy is also exchanged between the involved states. This work also addresses a question: In addition to that regarding localization, what other property of the system can be extracted from Shannon entropy? Insightful connection is discovered between Shannon entropy and the average value of confinement potential, Coulomb potential, and kinetic energy.

Entropic uncertainty as a predictor of avoided crossing for confined system

SynopsisAvoided Crossings are one of the unique spectroscopic features of confined atomic system. Shannon’s information entropy as a predictor of these phenomena by varying the perturbation (confinement strength) on ground state and some of excited states of H atom is studied in this work. In addition to the energy level repulsion at avoided crossing, it is observed that Shannon’s entropy also assures the exchange of information of involved states, and also validates entopic uncertainty.

A counter ion triggers stabilization of two geometrical isomers of a Ni(ii) dication diradical porphyrin dimer: the role of anion-π interactions.

Two geometrical isomers of a nickel(ii) dication diradical porphyrin dimer have been isolated selectively in pure forms by step-wise addition of the oxidant in the same reaction pot. Both isomers, stabilized exclusively by anion-π interactions, have unique and very distinct electronic and spectroscopic features and display an anion-induced charge/electron transfer phenomenon. Our work highlights the crucial role played by counter ions in controlling and stabilizing a variety of electronic structures and potentiates the effect of anion-π interactions in the chemical, biological and materials world.

Electronic fingerprints of Cr and V dopants in the topological insulator Sb2Te3

By combining scanning tunneling microscopy/spectroscopy and first-principles calculations, we systematically study the local electronic states of magnetic dopants V and Cr in the topological insulator (TI) Sb2Te3. Spectroscopic imaging shows diverse local defect states between Cr and V, which agree with our first-principle calculations. The unique spectroscopic features of V and Cr dopants provide electronic fingerprints for the co-doped magnetic TI samples with the enhanced quantum anomalous Hall effect. Our results also facilitate the exploration of the underlying mechanism of the enhanced quantum anomalous Hall temperature in Cr/V co-doped TIs.

Structural, vibrational and electronic absorption characteristics of the monohydrate organic salt of 2-amino-5-bromo-6-methyl-4-pyrimidinol and 2,3-pyrazinedicarboxylic acid: A combined experimental and computational study

The monohydrate 1:2 organic salt of 2-Amino-5-bromo-6-methyl-4-pyrimidinol (ABMP), also known as 5-Bromo-6-methylisocytosine, with 2,3-pyrazinedicarboxylic acid (PDCA) has been synthesized by slow evaporation technique. The hydrated salt has been characterized by single crystal X-ray diffraction (SCXRD) and observed to crystallize in the orthorhombic space group P212121. The infrared absorption spectroscopic technique combined with density functional theory (DFT) simulations have been employed to analyse the vibrational modes of the synthesized organic salt. Further, the FTIR spectra confirm that the salt formation from their unique spectroscopic feature as compared to its constituent molecules, PDCA and ABMP. The estimation of the optical band gap and maximum absorption wavelength of the hydrated organic salt have been performed using UV–Vis absorption spectroscopy. Degradation profile, as well as associated DTA peaks of the synthesized organic salt, have been critically analyzed by thermal gravimetric-differential thermal analysis (TG-DTA). Moreover, the Hirshfeld surface and associated fingerprint plot studies have been characterized the non-covalent interaction and their relative proportions to the present organic salt. The remaining important molecular properties like the frontier molecular orbital, nonlinear optical properties (NLO) and molecular electrostatic potential (MEP) map have also been studied for the above organic salt.

Investigation of the structural environment and chemical bonding of fluorine in Yb-doped fluorosilicate glass optical fibres

Fluorosilicate glass optical fibres are interesting hosts for rare-earth ions. When doped with ytterbium, for example, such fibres exhibit unique and beneficial fluoride-like spectroscopic features despite the host being predominantly silica. This work investigates the thermo-physical and chemical properties of Yb-doped fluorosilicate optical fibres in order to gain insight into the local structure about the rare earth and better understand the origins of their spectroscopic properties. Experimental findings, which suggest that the rare earth is embedded in a fluorine-rich environment in the fluorosilicate glass, are corroborated using molecular dynamic simulations.

Microwave energy-based manufacturing of hollow carbon nanospheres decorated with carbon nanotubes or metal oxide nanowires

Nanostructured hollow carbon spheres (HCNSs), with either carbon nanotube (CNT) or metal oxide nanowire (MONW) decoration on their surface, were synthesized as building materials with a great potential for the next-generation advanced applications. A well-established, polymeric latex NS synthesis method and a simply modified version of a microwave (MW) energy-based carbonization approach, i.e., Poptube, were systematically combined to obtain these HCNSs. Through this simple, facile, affordable and easily scalable “combined synthesis method,” it was managed to successfully produce HCNSs with unique morphological, spectroscopic, thermal and elemental features, all of which were strongly supported by both various material characterization test results and the relevant previous literature data. Thus, it is believed that the as-synthesized CNT or MONW decorated HCNSs (CNT-MONW/HCNS) from the above-mentioned method would soon become the materials of preference for the next-generation advanced applications in various science and engineering fields.

Tuning the BODIPY core for its potential use in DSSC: a quantum chemical approach

Boron dipyrromethene (BODIPY) is a highly promising candidate for use in dye-sensitized solar cell (DSSC), because of its attractive absorption characteristics such as strong extinction coefficients in the visible and near-IR ranges (70000–80000 $$\hbox {M}^{-1}$$ $$\hbox {cm}^{-1})$$ , large quantum yields, longer excited-state lifetime and also high solubility in many organic solvents. Moreover, the absorption peaks can be shifted towards longer wavelengths when functionalized at suitable positions of the BODIPY core. Herein, on the basis of density functional theory (DFT) and time-dependent DFT, we provide the opto-electronic properties of BODIPY core-functionalized dyes to see their applicability in organic DSSC. Our systematic analyses reveal that the 2,6 substituted dyes show better photovoltaic properties compared to the 3,5 substituted ones. On the basis of empirical relationship, we have also calculated the photo-induced electron injection times of some dye- $$\hbox {TiO}_{2}$$ composites, which seem to be in the ultrafast time scale, thus rendering them a promising candidate for DSSC applications. Our theoretical studies provide that judiciously designed BODIPY core-derived dyes show certain unique spectroscopic and electronic features that make them highly advantageous in DSSC applications as compared to other organic dyes.