Additional Absorption Band Research Articles

Enhanced optical and antimicrobial activities of mono Zn and bimetallic (Zn, Co), (Zn, Pd) ions modified MCM-41: structural and morphological investigation

Mono and bimetallic modified MCM-41(Mobil Composition of Matter No. 41): Zn-MCM (ZM), Zn/Co-MCM41 (ZCM), and Zn/Pd-MCM-41 (ZPM) molecular sieves were produced by a surfactant-assisted technique. The structural and textural features were examined through spectroscopic and analytical techniques. The XRD analysis indicated broadening of diffraction peaks and a shift towards higher 2-theta values in the metal-incorporated (M-MCM-41) samples, confirming the successful integration of metal atoms into the MCM-41 framework; it also highlighted the preservation of a hexagonal structure with reasonable regularity, emphasizing the influence of metal incorporation on the mesoporous architecture of MCM-41. N2 adsorption–desorption isotherms revealed type IV isotherms for all samples; the BET specific surface area decreased to 672.48, 667.90, and 562.50 m2/g in ZM, ZCM, and ZPM, respectively comparing to the unincorporated MCM-41 sample (1200 m2/g), indicating partial filling of mesopores by metal centers, as confirmed by TEM images. The diffuse reflectance spectra exhibited a noteworthy optical band gap reduction of MCM-41 (5.98 eV) upon the incorporation of Zn and Co/Zn ions, resulting in values of 5.86 and 5.24 eV, respectively, with refractive index values close to 2. Additional absorption bands energies are observed at 3.14, 3.18, and 1.70 eV in ZM, ZPM, and ZCM samples, respectively suggesting the suitability of the metal incorporated samples for the photocatalytic applications. The M-incorporated samples exhibited a decline in the transmission intensity accompanied by small shifts. The enhanced antimicrobial activity of the metal-incorporated samples, surpassing that of the pure MCM-41 against a variety of tested microorganisms, is attributed to the presence of incorporated metal species, which create a more acidic environment and substantially contribute to the heightened antimicrobial effectiveness. The ZM compound demonstrated potent inhibition against Bacillus cereus and Pseudomonas aeruginosa bacteria, displaying comparable efficacy to Ampicillin, as a reference antibiotic. Additionally, ZPM exhibited considerable inhibitory activity against Escherichia coli, surpassing the reference antibiotic and showing similar effectiveness against Bacillus cereus, Pseudomonas aeruginosa, and Salmonella typhimurium.

Structure and gamma attenuation behavior of copper ions in host glass from the system (P2O5–LiF–CaF2)

Copper-doped lithium calcium fluorophosphate glasses in the compositional system (60−x)P2O5·20LiF·20CaF2·xCuO (x = 0−3 mol%) were prepared using the conventional melt quenching technique. X-ray diffraction confirmed the amorphous, non-crystalline phase of the glasses. Optical absorption spectra indicated the presence of additional broad visible-NIR absorption bands upon CuO doping, attributed to distorted Cu2+ ions. Possible overlaps from Jahn-Teller distorted sites or clustering into nanodomains may contribute to band broadening. The direct optical bandgap was found to reduce from 3.89 eV to 1.17 eV with increasing CuO content. The study of physical parameters showed almost linear variation in density (2.62–2.95 g/cm3) and molar volume (40.45–35.29 cm3/mol) with incremental CuO substitution, explained by changes in structural packing efficiency and formation of Cu–O complexes. FTIR spectra revealed vibrations corresponding to phosphate structural groups. The simulation of radiation shielding parameters displayed steady improvements with higher CuO fractions, which were related to enhanced photon interactions via photoelectric absorption and Compton scattering.

Near-IR Capturing N-Methylbenzene Sulfonamide-Phenothiazine Incorporating Strong Electron Acceptor Push-Pull Systems: Photochemical Ultrafast Carrier Dynamics.

Unraveling the intriguing aspects of the intramolecular charge transfer (ICT) phenomenon of multi-modular donor-acceptor-based push-pull systems are of paramount importance considering their promising applications, particularly in solar energy harvesting and light-emitting devices. Herein, a series of symmetrical and unsymmetrical donor-acceptor chromophores 1-6, are designed and synthesized by the Corey-Fuchs reaction via Evano's condition followed by [2+2] cycloaddition retroelectrocyclic ring-opening reaction with strong electron acceptors TCNE and TCNQ in good yields (~60-85 %). The photophysical, electrochemical, and computational studies are investigated to explore the effect of incorporation of strong electron acceptors 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) and dicyanoquinodimethane (DCNQ) with phenothiazine (PTZ) donor. An additional low-lying broad absorption band extended towards the near-infrared (NIR) region suggests charge polarization after the introduction of the electron acceptors in both symmetrical and asymmetrical systems, leading to such strong ICT bands. The electrochemical properties reveal that reduction potentials of 3 and 6 are lower than those of 2 and 5, suggesting DCNQ imparts more on the electronic properties and hence largely contributes to the stabilization of LUMO energy levels than TCBD, in line with theoretical observations. Relative positions of the frontier orbitals on geometry-optimized structures further support accessing donor-acceptor sites responsible for the ICT transitions. Eventually, ultrafast carrier dynamics of the photoinduced species are investigated by femtosecond transient absorption studies to identify their spectral characteristics and target analysis further provides information about different excited states photophysical events including ICT and their associated time profiles. The key findings obtained here related to excited state dynamical processes of these newly synthesized systems are believed to be significant in advancing their prospect of utilization in solar energy conversion and related photonic applications.

Tunable white light emission in antimony doped vacancy-ordered double perovskite Cs2ZrCl6 nanocrystals

Design of stable white-light emitting materials based on the emerging lead-free metal halide colloidal nanocrystals is in urgent demand for lighting technology innovation. Herein, we developed a facile hot-injection method and optimize the synthesis conditions to prepare Sb3+ doped Cs2ZrCl6 nanocrystals with good uniformity and crystallinity. Sb3+ ions were doped into the Cs2ZrCl6 lattice and proved to occupy the sites of Zr4+ ions, generating additional absorption bands at lower energy and new emission band centered at 620 nm apart from the absorption and emission from the host. The emission at 620 nm from Sb3+ ions could be prompted by an energy transfer process between the host STEs and Sb3+ ions. Moreover, benefiting from two broad emission bands from singlet and triplet states of Sb3+ ions in Cs2ZrCl6 nanocrystals, we obtained tunable white-light-emitting nanocrystals by adjusting the dopant concentration. Our study provides a reliable method to design efficient single-emitter-based white-light emitting metal halide nanocrystals and promote their development in the field of lighting and displays.

Water Speciation and Storage Capacity of Olivine under the Reduced Fluid—Peridotite Interaction

The key features of the interaction between peridotites of the continental lithospheric mantle and reduced hydrocarbon-rich fluids have been studied in experiments conducted at 5.5 GPa and 1200 °C. Under this interaction, the original harzburgite undergoes recrystallization while the composition of the fluid changes from CH4-H2O to H2O-rich with a small amount of CO2. The oxygen fugacity in the experiments varied from the iron-wustite (IW) to enstatite-magnesite-olivine-graphite/diamond (EMOG) buffers. Olivines recrystallized in the interaction between harzburgite and a fluid generated by the decomposition of stearic acid contain inclusions composed of graphite and methane with traces of ethane and hydrogen. The water content of such olivines slightly exceeds that of the original harzburgite. Redox metasomatism, which involves the oxidation of hydrocarbons in the fluid by reaction with magnesite-bearing peridotite, leads to the appearance of additional OH absorption bands in the infrared spectra of olivines. The water content of olivine in this case increases by approximately two times, reaching 160–180 wt. ppm. When hydrocarbons are oxidized by interaction with hematite-bearing peridotite, olivine captures Ca-Mg-Fe carbonates, which are products of carbonate melt quenching. This oxidative metasomatism is characterized by the appearance of specific OH absorption bands and a significant increase in the total water content in olivine of up to 500–600 wt. ppm. These findings contribute to the development of criteria for reconstructing metasomatic transformations in mantle rocks based on the infrared spectra and water content of olivines.

One-Step Cascade Synthesis of ortho-bay-Imidazolo-Extended Perylene Biscarboximides (OBISIM) and Their Application as Broad-Spectrum Fluorescent Dyes.

A one-step synthesis of perylene dyes with lateral extension by condensed imidazoles in a cascade reaction of sodium amide and benzonitrile is described in which multiple extensions can be controlled by the reaction conditions. The extensions lead to bathochromic shifts in absorption and fluorescence while maintaining high fluorescence quantum yields. The condensed imidazole units cause additional absorption bands in the hypsochromic visible region, resulting in broad-band absorbers. Multiple extensions of the aromatic system enable the NIR spectral approach of the spectra. Energy transfer (fluorescence resonance energy transfer, FRET) of dyads with perylene biscarboximides is very efficient and achieves quantum yields close to unity regardless of the lengths and orientation of the spacer. Applications as broad-band-absorbing fluorescent dyes, such as in solar collectors, are discussed.

Exploring film forming ability and improving its bioadhesiveness by thiolation of mucilaginous polysaccharides from Cassia uniflora seeds for drug delivery application

The objectives of the present work were to explore film forming ability of mucilaginous polysaccharides obtained from Cassia uniflora seeds and improving its bioadhesive potential by thiolation for drug delivery and other applications. Thiolation was achieved by esterification reaction with thioglycolic acid. The modification was confirmed by performing and comparing its zeta potential, DSC, and spectrophotometric characterization by FTIR and NMR with unmodified mucilaginous polysaccharide. The modified mucilaginous polysaccharides FTIR spectra showed an additional absorption band at 2565 cm−1 and new shifts appeared in the 1H (δ 3.24 and at δ 3.44 ppm) and 13C NMR spectra's (21.56 ppm) confirming the esterification of mucilaginous polysaccharides. The prepared films of thiolated and unmodified mucilaginous polysaccharides were evaluated for various parameters like thickness, pH, and weight measurement, The film formulation had a thickness of 0.16 to 0.18 mm, pH in the range of 6.79 to 7.09 and weight uniformity 0.89 to 0.94 mg.The results reveal that the films based on thiolated material improved bioadhesive properties after thiolation. The SEM photographs revealed a smooth surface of film formulations. The diclofenac-loaded film of thiolated mucilaginous polysaccharide also showed >1.5-fold an increase in in-vitro drug release and exhibited non Fickian transport mechanism. These findings could increase the possible applications of chemically modified-thiolated mucilaginous polysaccharides of Cassia uniflora seeds in drug delivery.

Synthesis and spectral properties of mixed-ligand Zr and Hf phthalocyanine complexes with out-of-plane coordinated alkylamino-β-ketoenolate chromophores and decanoate

The development of novel materials based on modification of phthalocyanines is promising for various applications in science, medicine and technology. Here mixed-ligand Zr and Hf phthalocyanine complexes with out-of-plane coordinated alkylamino-β-ketoenolate chromophores and decanoate were synthesized for the first time. Complexes were obtained by one stage reaction of bis(decanoato)zirconium and hafnium phthalocyanines with alkylamino-β-ketoenols that resulted in replacement of only one decanoate ligand with the alkylamino-β-ketoenol. Therefore, mixed-ligand Zr and Hf complexes with two chromophore systems (phthalocyanine and alkylamino-β-ketoenol) were synthesized by using four different alkylamino-β-ketoenols, and their structural characterizations were carried out by using some spectroscopic methods: 1H NMR, UV–Vis, IR and MALDI TOF MS. In the UV–Vis spectra of the obtained complexes, the absorption bands characteristic for phthalocyanine system were observed along with additional absorption band of out-of-plane ligand (in the region 440–480 nm). The fluorescence spectra of investigated compounds are characterized by a maximum at about 690 nm, which corresponds to the emission of the phthalocyanine macrocycle, while the emission of alkylamino-β-ketoenol ligand is not observed.

Effect of proton irradiation on optical properties and defect formation in crystals Gd<sub>3</sub>Al<sub>x</sub>Ga<sub>5–x</sub>O<sub>12</sub> (x = 2, 3)

The influence of proton irradiation with a dose of 50 Mrad (Si) on the optical properties and defect formation in crystals of the gadolinium-aluminum-gallium garnet with the substitution of aluminumand gallium in the cationic sublattice: Gd3Al2Ga3O12 (Al: Ga = 2:3) and Gd3Al3Ga2O12 (Al: Ga = 3:2) was studied. After proton irradiation, color of crystals changes: an additional absorption band appears in the transmittance of each crystal in the wavelength range 400–500 nm. This occures due to the formation of induced structural defects as color centers. The refractive indices n(λ) were determined by the Brewster spectrophotometric method and practically did not change for Al:Ga = 2:3 crystals, but significantly increased for Al:Ga = 3:2. There is a noticeable increase in the attenuation of the light in spectral dependences, which also indicates the formation of additional structural defects.

Light-Induced Liposomal Drug Delivery with an Amphiphilic Porphyrin and Its Chlorin and Bacteriochlorin Analogues.

The development of targeted drug delivery mechanisms in the human body is a matter of growing interest in medical science. The selective release of therapeutic agents at a specific target site can increase the therapeutical efficiency and at the same time reduce the side effects. Light-sensitive liposomes can release a drug by an externally controlled light trigger. Liposomes containing photosensitizers that can be activated in the longer wavelength range (650-800 nm) are particularly intriguing for medical purposes. This is because light penetration into a tissue is more efficient within this wavelength range, increasing their potential applications. For this study, liposomes with an encapsulated amphiphilic photosensitizer, the porphyrin 5,10-DiOH (5,10-di(4-hydroxyphenyl)-15,20-diphenyl-21,23H-porphyrin), its chlorin (5,10-DiOH-chlorin) and its bacteriochlorin (5,10-DiOH-bacteriochlorin) were synthesized. The porphyrin 5,10-DiOH showed previously effective cargo release after liposomal encapsulation when irradiated at a wavelength of 420 nm. The new synthesized chlorin and bacteriochlorin photosensitizers show additional absorption bands in the longer wavelength range, which would enable excitation in deeper layers of tissue. Effective cargo release with chlorin at a longer wavelength of 650 nm and bacteriochlorin at 740 nm was possible. Irradiation of chlorin allowed more than 75% of the cargo to be released and more than 60% for bacteriochlorin. The new liposomes would enable selective drug release in deeper tissue layers and expand the range of possible applications.

Optical Spectra of Composite Materials Based on Molybdenum- Containing Nanoparticles and High-Pressure Polyethylene

Molybdenum-containing composite nanomaterials are synthesized by the thermal decompositionof molybdenum hexacarbonyl in a solution-melt of polyethylene in mineral oil. The concentration of a metalcontainingfiller in the composite materials varied from 1 to 20 wt %. A technique for preparing film samplesfor spectroscopic studies is developed, and the samples obtained are studied by UVI, IR, and Raman spectroscopy.It is found that additional absorption bands appear in the IR range, whose intensity depends on theconcentration of molybdenum-containing nanoparticles in the composite materials. The spectral characteristicsof Raman scattering show that all samples are characterized by the stretching of the C–C bond. In thevisible light region, the spectrum of nanocomposites has a flat edge of its own absorption located in the regionof wave numbers (18–31) × 103 cm–1.

Optical and Surface Structure Modification of Gallium Arsenide

The surface morphology modification and optical property modification of semi-insulating gallium arsenide sample implanted with 100 keV silicon ions with the fluences ranging between 5 × 10[Formula: see text] and 4 × 10[Formula: see text] ion cm[Formula: see text] were analyzed using scanning electron microscopy and UV–Vis–NIR spectroscopy study. Scanning electron microscopy study revealed pore-like structure formation on the surface of gallium arsenide samples after silicon ion implantation. The size of these pore-like structures was found to increase with increasing ion fluence. Energy dispersive X-ray analysis showed an increase in silicon concentration in the gallium arsenide sample after silicon ion implantation with increasing ion fluence. The UV–Vis–NIR spectroscopy study revealed a decrease in optical transmission for silicon ion implanted gallium arsenide sample with increasing ion fluence. An additional absorption band was observed for the gallium arsenide sample implanted with the highest fluence (4 × 10[Formula: see text] ion cm[Formula: see text]. Urbach tail energy was found to increase with respect to ion fluence.

Indium containing sillenite semiconductor: Synthesis, structural, spectroscopic, and thermogravimetric analysis

AbstractSillenite‐type ceramics are non‐centrosymmetric phases of ongoing research interest because of their structural defects and optoelectronic properties. We report a series of sillenite compounds with a general composition Bi12(Bi3+4/5−3xIn3+5x□1/5−2x)O19.2+3x□0.8−3x for x = 0.03–0.27 to understand how the crystal–physicochemical properties change with a successive filling of empty Bi3+ positions in the tetrahedral site by In3+ cation. Conventional solid‐state synthesis method is used to prepare the microcrystalline samples. Each sample is characterized by X‐ray diffraction, Raman, UV/Vis diffuse reflectance spectroscopy, and thermogravimetry (TG/DSC). X‐ray powder data Rietveld refinement reveals that phase‐pure samples can be obtained for x = 0.03–0.08 in the space group I23. Appearance of starting In2O3 as minor phases with the final products for 0.10 < x < 0.27 suggests for xmax = 0.08. The successive decrease of the lattice parameter indicates the incorporation of smaller In3+ cations in the structure. The effect of the lone electron pairs of Bi3+ and the structural cation vacancies lead to the modification of the interatomic bond lengths. At least one Raman active phonon mode shows hardening for decreasing cation vacancy concentration in the system. The bandgap energy increases with increasing indium content. An additional absorption band at lower energy for x = 0.03–0.08 complements the theoretical study, which completely disappears for x > 0.08. The stronger In–O bonds play pivotal roles in the thermal stability of the phases studied by TGA/DSC analysis.

INFRARED SPECTROSCOPIC ANALYSIS OF COMPLEX OXIDE CATALYST 50%Cu3(PO4)2•50%Ni3(PO4)2

It is established that the frequencies and intensities of the absorption bands of the infrared spectra of the obtained air-dried sample 50%Cu3(PO4)2∙50%Ni3(PO4)2 and calcined at the optimum heat treatment temperature of 600оС are characterized by significant absorption in the valence (3460-3020 cm-1) and strain (2360-1400 сm-1) vibrations of hydroxyl OH-groups of water molecules. Valence vibrations of phosphate ion are most manifested in dehydration products in the form of clear bands in the absorption frequency range 1110-410 сm-1. For the investigated sample, three absorption bands were observed in the region: 3188,72 сm-1, 1621,84 сm-1 та 1434,78 сm-1. They confirm the existence of two types of crystalline hydrate water molecules, which are characterized by different hydrogen bonding energies. In the process of heat treatment of the synthesized sample in the temperature range of 120-700оС , the process of dehydration occurs. In this case, the intensity of the absorption bands in the region of valence and strain vibrations of water molecules gradually decreases in the obtained IR spectra. The phenomenon of complication of the spectrum of orthophosphate ion by additional absorption bands is obviously associated with the distortion of the tetrahedron structure in real crystals and the reduction of its symmetry. It can be a consequence of both low symmetry of the environment and perturbation of the orthophosphate anion РО43– by water molecules when intermolecular hydrogen bonds occur. It may also be due to possible additional coordination of orthophosphate anion with metal cations Сu2+ and Ni2+. Calcination of the sample at the final heat treatment temperature of 700оС leads to an anhydrous orthophosphate system. This will lead to a decrease in the value of surface acidity and catalytic inertness of the sample.
 Keywords: catalysts; heterogeneous catalysis; phosphates; complex oxides; oxidation; n-alkanes; hydrocarbons; ethane; ethylene; IR spectroscopy.

Synthesis and Characterization of the Properties of (1-x)Si3N4-xAl2O3 Ceramics with Variation of the Components.

The aim of this paper is to study the effect of variation in the component ratio of (1-x)Si3N4-xAl2O3 ceramics on the phase composition, strength and thermal properties of ceramics. To obtain ceramics and their further study, the solid-phase synthesis method combined with thermal annealing of samples at a temperature of 1500 °C typical for the initialization of phase transformation processes was used. The relevance and novelty of this study lies in obtaining new data on the processes of phase transformations with a variation in the composition of ceramics, as well as determining the effect of the phase composition on the resistance of ceramics to external influences. According to X-ray phase analysis data, it was found that an increase in the Si3N4 concentration in the composition of ceramics leads to a partial displacement of the tetragonal phase of SiO2 and Al2(SiO4)O and an increase in the contribution of Si3N4. Evaluation of the optical properties of the synthesized ceramics depending on the ratio of the components showed that the formation of the Si3N4 phase leads to an increase in the band gap and the absorbing ability of the ceramics due to the formation of additional absorption bands from 3.7-3.8 eV. Analysis of the strength dependences showed that an increase in the contribution of the Si3N4 phase with subsequent displacement of the oxide phases leads to a strengthening of the ceramic by more than 15-20%. At the same time, it was found that a change in the phase ratio leads to the hardening of ceramics, as well as an increase in crack resistance.

Transient “cis-Peak” Is Present in Excited-State Absorption of Central-cis Isomers of Carotenoids

Application of femtosecond time-resolved transient absorption spectroscopy on all-trans and central-cis isomers of two exemplary carotenoids, lutein and spirilloxanthin, performed at room and cryogenic temperatures in the spectral range expanded toward UV revealed new spectroscopic transient features for the cis isomers. Notably, particularly for the central-cis spirilloxanthin, a very distinct additional transient absorption band is observed on the short wavelength side of the main excited-state absorption band of the S1 state, having the same temporal characteristics as the latter one. This band is absent in transient absorption spectra of all-trans isomers, suggesting it could be assigned to "transient cis-peak." Overall, the results show that the "transient" counterpart of the spectral marker of cis-isomers of carotenoids, or the so-called cis-peak, is detectable in the excited-state absorption spectrum and could be attributed to electronic transition from the S1 state. This new transient spectral band could be very useful for spectroscopic experiments targeting the dynamics of carotenoid isomers and their severely distorted forms.

Effects of peripheral ring fluorination on the photophysical properties of hexaarylbenzenes

Hexaarylbenzenes (HABs) exhibit interesting photophysical properties that originate from the through-space charge-transfer interactions between their six twisted peripheral aromatic rings. Although the introduction of fluorine atoms into π-conjugated structures allows one to effectively control their electron density distribution and aggregation behavior, the effects of peripheral ring fluorination on HAB properties remain underexplored. This paper describes the syntheses and photophysical properties of three unsymmetrical HABs and their symmetrical regioisomers, namely compounds belonging to 0F (no fluorine atoms on the short molecular axes of the peripheral aromatic rings), 4F (four fluorine atoms as substituents on the short molecular axes of the aromatic rings with CF3 end groups), and 8F series (four fluorine atoms on the short molecular axes of each of the peripheral aromatic rings). All the HABs exhibited blue photoluminescence both in solution and in crystalline form. Molecules in the 4F series exhibited an increase in their Stokes shift with increasing solvent polarity and featured superior intramolecular charge-transfer properties, which produced a significant redshift of the PL band of the unsymmetrical molecule compared to that of its symmetrical counterpart. It is noteworthy that the 4F series exhibited photochromic behavior, that is, an additional absorption band in the longer-wavelength region was observed upon irradiating it with 280-nm UV light, and consequently the colorless solution acquired a yellow color . Thus, the partial fluorination of the HAB scaffold (4F series) produced photochromic behavior, while its other photophysical properties were preserved.

Ethylenediamine control of the supramolecular chemistry of magnesium phthalocyanine

The two axially ligated magnesium phthalocyanine derivatives, MgPc(EDA) and MgPc(H2O), were obtained directly by thermal reaction of MgPc in ethylenediamine (EDA) solution. Both complexes, MgPc(EDA) and MgPc(H2O), co-crystallize with the water molecule yielding good-quality single crystals 1. Presence in the crystals 1 the MgPc(H2O) results from the high affinity of MgPc to trace of water in the solvent as well as due to the high affinity of MgPc to moisture in air. The axially substituted magnesium phthalocyanine derivatives, MgPc(EDA) and MgPc(H2O), are, as expected, non-planar MPcs and interact with each other through a solvated water molecule to form supramolecular aggregates linked by NH…O and OH…N hydrogen bonds. Supramolecular arrangement of the non-planar MgPc-derivatives in crystal is characterized by a reduction of π···π interactions and an improvement in inter-system crossing in relation to parent MgPc, which results in increase its solubility and improved photophysical and photochemical properties. The aggregation behavior of the MgPc(EDA) and MgPc(H2O) complexes building crystals 1 in EDA and ethanol solutions was investigated. The MgPc(EDA) and MgPc(H2O) complexes building crystals 1 in an ethanol solution are stable, while in the EDA solution, one of them undergoes demetallation with formation of a metal-free phthalocyanine, since the UV–vis absorption spectrum versus time shown additional electronic absorption band in the region known as the Q-band which is typical for the spectrum of H2Pc. Besides, the UV–Vis spectroscopic characterization of the crystals 1 in solutions, the diffuse reflectance spectroscopic (DSR) characterization on the solid sample of 1 was performed. The DSR spectra of 1 exhibit broad bands with a small blue-shift that might be attributed to a larger exciton coupling resulting from closer contacts between the molecules than in solution. In order to support and verify the experimental results, the DFT and time-dependent (TD) DFT calculations were performed.

Tradeoff between Intermolecular Interaction and Backbone Disorder by High Molecular Dipole Block for Improving Blend Morphology of Polymer Solar Cells

AbstractConstructing terpolymer has attracted increasing attention as a strategy to improve the performance of polymer solar cell. Terpolymer usually offers an opportunity to lower the frontier molecular orbital energy level, introduces additional absorption band and sometimes optimizes the morphology of the active blend. Generally, the additional segment in terpolymer backbone inevitably introduces backbone disorder, which causes entropy rises. However, selecting a suitable dipole unit introduces extra driving forces for crystallization by enhancing intermolecular interactions. This provides a handy knob for tradeoff between intermolecular interaction and backbone disorder, thus regulating the blend morphology. Herein, a high dipole and electron‐deficient group of pyrrolo[3,4‐f]benzotriazole‐5,7(6H)‐dione (TzBI) is incorporated into the high‐performance donor polymer and a series of terpolymers with different content of TzBI are designed. As expected, the morphology is optimized gradually for improving charge generation and charge transport, also suppressing charge recombination. The champion device with 10% TzBI exhibited a power conversion efficiency (PCE) of 18.36%, which is 5% increase compared to the controlled device. This study presents a charming terpolymer strategy by highly electron‐deficient and high dipole segment to realize a tradeoff between intermolecular interaction and backbone disorder, facilitating the optimization of morphology and elevation of fill factor and device efficiency.

STUDY OF THE EFFECT OF ZCO CERAMIC PHASE COMPOSITION ON OPTICAL AND THERMOPHYSICAL PROPERTIES

The work is devoted to the study of optical and thermophysical properties of promising materials for nuclear power of a new generation - inert matrices of nuclear dispersed fuel based on ZrO2 – CeO2 (ZCO) doped with Y2O3. Interest in this class of materials is due to great prospects in the field of replacing the traditional type of nuclear fuel with uranium-free dispersed nuclear fuel, which is based on a technological solution using plutonium as a fissile element, placed in a dispersed inert matrix based on oxide or nitride ceramics. The purpose of this work is to study the effect of doping of ZCO ceramics with Y2O3 on the optical and heat-conducting properties. During the study, it was found that an increase in the concentration of the Y2O3 dopant leads to the formation of a highly ordered CeZrO4 phase, the presence of which leads to the appearance of an additional absorption band in the region of 550 – 650 nm, as well as a decrease in the transmission value in the region of 400 – 700 nm. To evaluate the results obtained, the methods of optical UV spectroscopy and heat flux determination were applied. It has been found that doping with Y2O3 leads to the formation of a highly ordered CeZrO4 phase, the formation of which leads to the appearance of additional spectral absorption lines, as well as a shift in the band gap to the region of low energies. During analysis of the thermophysical parameters, it was found that a change in the phase composition leads to an increase in the thermal conductivity coefficient by more than 40 – 60 %.