High electron mobility fluorinated indacenodithiophene small molecule acceptors for organic solar cells

Indacenodithiophene (IDT) derivatives are kinds of the most representative and widely used cores of small molecule acceptors (SMAs) in organic solar cells (OSCs). Here we systematically investigate the influence of end-group fluorination density and position on the photovoltaic properties of the IDT-based SMAs IDIC-nF (n = 0, 2, 4). The absorption edge of IDIC-nF red-shifts with the π-π stacking and crystallinity improvement, and their electronic energy levels downshift with increasing n. Due to the advantages of J_sc and FF as well as acceptable V_oc, the difluorinated IDIC-2F acceptor based OSCs achieve the highest power conversion efficiency (PCE) of 13%, better than the OSC devices based on IDIC and IDIC-4F as acceptors. And the photovoltaic performance of the PTQ10: IDIC-2F OSCs is insensitive to the active layer thickness: PCE still keep high values of 12.00% and 11.46% for the devices with active layer thickness of 80 and 354 nm, respectively. This work verifies that fine and delicate modulation of the SMAs molecular structure could optimize photovoltaic performance of the corresponding OSCs. Meanwhile, the thickness-insensitivity property of the OSCs has potential for large-scale and printable fabrication technology.     

Fluorination-substitution effect on all-small-molecule organic solar cells

Due to the strong crystallinity and anisotropy of small molecules, matched molecular photoelectric properties and morphologies between small molecules and non-fullerene acceptors are especially important in all-small-molecule organic solar cells(OSCs).Introducing fluorine atoms has been proved as an effective strategy to achieve a high device performance through tuning molecular energy levels, absorption and assembly properties. Herein, we designed a novel benzodithiophene-based small molecule donor BDTF-CA with deep highest occupied molecular orbital(HOMO) energy level. All-small-molecule OSCs were fabricated by combing non-fullerene acceptor IDIC with different fluorine-atom numbers. Two or four fluorine atoms were introduced to the end-capped acceptor of IDIC, which are named as IDIC-2 F and IDIC-4 F, respectively. With the increase of fluorination from IDIC to IDIC-4 F, the open circuit voltage(V_(oc)) of the devices decreased, while hole and electron mobilities of the active layers increased by one order of magnitude. Contributed to the most balanced V_(oc), short-circuit current(J_(sc)) and fill factor(FF), the device based on BDTF-CA/IDIC-2 F achieved the highest power conversion efficiency of 9.11%.     

Ion pairing in NHC gold(I) olefin complexes: A combined experimental/theoretical study

The relative anion-cation orientation in [(NHC)Au(alkene)]BF₄ ion pairs [NHC = N-Heterocyclic Carbene = 1,3-bis(di-iso-propylphenyl)-imidazol-2-ylidene (IPr) and 4,5-dimethyl-N,N′-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene (^MeIPr); alkene = 4-methyl-1-pentene, 2,3-methyl-2-butene and 4-methylstyrene] has been investigated by combining ¹⁹F,¹H-HOESY NMR spectroscopy in CD₂Cl₂ and a detailed analysis of the Coulomb potential of the cationic fragment through DFT calculations. Two main orientations have been found where the anion locates close to the imidazole ring (NHC-side) and close to the olefin (olefin-side). The NHC-side orientation is always predominant (65-83%) while the exact position of the anion in the olefin-side is finely tuned by the nature of olefin substituents. In all cases, the counterion resides far away from the gold site, the latter carrying only a small fraction of the positive charge.     

Design a thieno[3,2-b]thiophene bridged nonfullerene acceptor to increase open-circuit voltage,short-circuit current-density and fill factor via the ternary strategy

In this study, we report a new small molecule acceptor (named TT-4F) which uses 3,6-dimethoxylthieno[3,2-b]thiophene (TT) as the π-bridge. Addition of 0.05 weight ratio amount of TT-4F into the host binary blend of PTB7-Th:IEICO-4F, resulting in a ternary blend in a weight ratio of 1:1:0.05, enables increased open-circuit voltage (V_oc), short-circuit current-density (J_sc), and fill-factor (FF) at the same time. Finally, 12.1% efficiency is obtained. Compared to the 3-(2-ethylhexyloxylthiophene) bridge on IEICO-4F, the additional methoxyl group on the TT-6 position is involved in the lowest unoccupied molecular orbital (LUMO) and the larger π-system on TT increases the electron-donating nature, both of which help to raise the LUMO level, one reason of the increased V_oc. Upon addition of 0.05 TT-4F, the hole mobility is increased, the monomolecular recombination is reduced, and the charge dissociation and collection is enhanced. All of these contribute to the increased J_sc and FF.     

Origin of formation of blue-shifted aggregates including H-aggregates in mixed Langmuir–Blodgett films of merocyanine dye investigated by polarized visible and infrared spectroscopy

The structure of a merocyanine dye (MS) in red- and blue-shifted aggregates involving J- and H-aggregates in mixed LB films of MS–arachidic acid (C₂₀) binary and MS–C₂₀-n-octadecane (AL₁₈) ternary systems ([MS]:[C₂₀]:[AL₁₈] = 1:2:x; x = 0, 1.0, 2.0, 3.0, 4.0 and 5.0) fabricated using an aqueous subphase containing Cd²⁺ ions has been investigated by means of polarized visible and infrared spectroscopy. Not only the AL₁₈ molecules mixed as a third component but also the Cd²⁺ ions added to distilled water for the subphase used turn out to be the significant elements for the formation of the MS aggregates in all the ternary systems. It has been found that the degree of the MS intramolecular charge transfer strongly depends on the aggregation states; the J-aggregate (x = 0), H-aggregate (x = 1.0), oligomer (x = 2.0) and relatively small aggregates (x = 3.0, 4.0 and 5.0), and that the stabilization by the intramolecular charge transfer for the formation of the MS aggregates is induced according to the individual aggregation states. The gauche conformation is clarified to be slightly involved in the MS hydrocarbon chains for all the binary and ternary systems. The long axis of the MS hydrocarbon chains in the J-aggregates, being fairly tilted from the film normal, gradually approaches to the film normal with the increasing AL₁₈ content up to x = 2.0 with the orientation of the long axis of the MS hydrocarbon chains remaining constant in the subsequent ternary systems. It can be concluded that the formation of the red- and blue-shifted aggregates is ascribed to the difference in the MS slippage which can also be regulated by the degree of the orientation of the MS hydrocarbon chains, and that the decrease in the size of the MS aggregates accompanied by the increasing AL₁₈ content is due to the blocking by the AL₁₈ molecules being out of the empty space on the MS chromophore.     

Phase diagram for the hexane-acetonitrile-tri-<Emphasis Type="Italic">n</Emphasis>-butyl phosphate-solvated thorium(IV) nitrate ternary liquid system

Phase diagrams of the hexane-acetonitrile-[Th(NO₃)₄(TBP)₂] liquid ternary system were studied at various temperatures. The system consists of two pairs of incompletely miscible liquids: hexane-acetonitrile and [Th(NO₃)₄(TBP)₂]-hexane. The two-liquid field in the [Th(NO₃)₄(TBP)₂]-hexane system decreases with increasing temperature; the upper critical solution temperature T _cr = 337.85 ± 0.25 K. The temperature effect on the immiscibility field in the hexane-acetonitrile system is insignificant. The title ternary liquid system is characterized by two homogeneous liquid fields and one two-phase liquid field at T < 338 K. One phase is depleted of acetonitrile and contains variable proportions of [Th(NO₃)₄(TBP)₂] and hexane; the other contains variable proportions of acetonitrile and [Th(NO₃)₄(TBP)₂] and a small proportion of hexane. With rising temperature, the two-phase field narrows and deforms, whereas the homogeneous liquid fields expand. At T > 338 K, the system transforms into a ternary liquid system with one pair of incompletely miscible liquids (hexane-acetonitrile).     

Etude du parametre d'interaction polymere-polymere pour le systeme ternaire solvant-polydimethylsiloxane-polystyrene. Influence de la concentration et de la masse moleculaire

This paper presents the results of a study of the thermodynamic properties of a ternary system viz. solvent (ethylacetate or benzene)-polydimethylsiloxane-polystyrene. The interaction parameter between the two polymers χ₂₃, determined both from light scattering and studies of the critical conditions of phase separation, has been studied as a function of the molecular weights of the two polymers. Using a polystyrene of fixed molecular weight, we observe a large decrease in χ₂₃ for increasing molecular weight of polydimethylsiloxane. When the molecular weights of the two polymers are very high, the parameter χ₂₃ becomes very small (of the order of 0.01). The values of χ₂₃ obtained for these two polymers are compared to those found for comparable systems, viz. polystyrene-polyisobutene and polydimethylsiloxane-polyisobutene.     

Crystallographic, electronic and magnetic studies of Ce4Ni6Al23: a new ternary intermetallic compound in the cerium-nickel-aluminum phase diagram

The Al-rich portion of the ternary Ce-Ni-Al has been investigated and a new ternary phase of composition Ce₄Ni₆Al₂₃ has been found. This compound crystallizes in the monoclinic space group C2/m with the cell parameters a=16.042(8), b=4.140(4), c=18.380(8) Å and β=113.24(5)°. The structure has been determined by single crystal X-ray diffraction. The local environment of Ni and Ce is close to what is observed in the CeNi₂Al₅ and CeNiAl₄ structures. Band structure calculations, using the tight-binding-linear muffin-tin orbital-atomic-spheres approximation (TB-LMTO-ASA) method, have been performed to understand the electronic structure of Ce₄Ni₆Al₂₃ and the results are discussed in connection with those two other Ce-Ni-Al intermetallic compounds, which possess heavy-fermion behavior. Magnetic and heat capacity measurements have also been measured to analyze the low-temperature magnetic behavior of this new compound.     

Cooperative Effect of Noncovalent Interactions on Tetrel Bonding in Halogenated Silanes

Tetrel bond, a weak noncovalent interaction between the σ-hole of a Group IV element (silicon in our case) and the cloud of an electronegative element (oxygen in our case) is the focus of this work. The percentage strengthening of tetrel bond has been investigated by optimizing 16 binary complexes of halogenated silane and water of general formula SiX_nH_4−n−H₂O and 16 ternary complexes, of general formula NaX−SiX_nH_4−n−H₂O, where X=F, Cl, Br and I and n=1, 2, 3 and 4 at various levels of theory defined within the formalism of density functional theory (DFT). With the addition of NaX, tetrel bond between Si and O in SiX_nH_4−n−H₂O gets strengthened up to 49 %, owing to cooperativity effect exerted by hydrogen bonding between X and H in the ternary complex NaX−SiX_nH_4−n−H₂O. In the series of complexes studied here, overall stabilization due to cooperativity lies between 10 kJ/mol to 170 kJ/mol. This large extent of reinforcement due to cooperativity has never been showcased before. The exceptional stabilization and reinforcement owe its genesis to the transformation of the ternary complex into a cluster orchestrated by the H-bonding in most of the cases and covalent bonding in few of the cases.     

Collisional depolarization of excited114Cd 5s5p 3 P 1 atoms by collisions with molecular gases

Depolarization of excited¹¹⁴Cd 5s5p ³ P ₁ atoms induced by collisions with various molecular gases (N₂, H₂, D₂, CO, CO₂, CH₄, C₂H₆, C₂H₄) has been investigated using polarized fluorescence spectroscopy. After pulsed optical excitation of the Cd 5³ P ₁ level with appropriately polarized light the temporal behaviour of Zeeman quantum beats has been observed showing the influence of collisional destruction of orientation and alignment. By analyzing the signal curves at different molecular gas pressures the corresponding depolarization cross sections for¹¹⁴Cd atoms in the 5³ P ₁ state have been obtained. With regard to a test of a nuclear spin decoupling model for the collisions the cross sections were compared with previously measured hyperfine structure transfer cross sections of¹¹³Cd 5s5p ³ P ₁ atoms.     

Thermodynamic study of sodium-iron oxides: Part II. Ternary phase diagram of the Na-Fe-O system

Studies on ternary phase diagrams of the Na-Fe-O system have been carried out from the thermodynamic point of view. Thermodynamic data of main ternary Na-Fe oxides Na₄FeO₃(s), Na₃FeO₃(s), Na₅FeO₄(s) and Na₈Fe₂O₇(s) have been assessed. A user database has been created by reviewing literature data together with recent DSC and vapor pressure measurements by the present authors. New ternary phase diagrams of the Na-Fe-O system have been constructed from room temperature to 1000 K. Stable conditions of the ternary oxides at 800 K were presented in predominance diagram as functions of oxygen pressure and sodium pressure.     

Synthesis, structure characterization and optical properties of a new tripotassium cadmium pentaborate, K3CdB5O10

A new ternary borate oxide, K₃CdB₅O₁₀, has been synthesized by solid-state reaction at 580 °C. The compound crystallizes in the monoclinic space group P2₁/n with a=7.6707 (7) Å, b=19.1765 (17) Å, c=7.8784 (6) Å, β=115.6083 (49)°, and Z=4. The crystal structure consists of a two-dimensional infinite [CdB₅O₁₀] layer, which forms by connecting isolated double ring [B₅O₁₀] groups and CdO₄ tetrahedra. K atoms filling in the interlayer and intralayer link the layers together and balance charge. The IR spectrum has been studied and confirmed the presence of both BO₃ and BO₄ groups, and the UV-vis-IR diffuse reflectance spectrum exhibits a band gap of about 3.4 eV. The DSC analysis proves that K₃CdB₅O₁₀ is a congruent melting compound.     

Electron charge distribution of CaAl2−xZnx: Maximum entropy method combined with Rietveld analysis of high-resolution-synchrotron X-ray powder diffraction data

Using short wavelength X-rays from synchrotron radiation (SPring-8), high-resolution powder diffraction patterns were collected. In order to study both the structural relationship and the mechanism of stability in the CaAl_2−xZn_x system, among the Laves phases (MgCu₂ and MgNi₂ type) and KHg₂-type structures, the charge density distribution of CaAl_2−xZn_x as a function of x was obtained from the diffraction data by Rietveld analysis combined with the maximum entropy method (MEM). In the MEM charge density maps overlapping electron densities were clearly observed, especially in the Kagomé nets of the Laves phases. In order to clarify the charge redistribution in the system, the deformation charge densities from the densities formed by the constituent free atoms are discussed. In the ternary MgNi₂-type phase, partial ordering of Al and Zn atoms is observed, a finding that is supported by ab-initio total energy calculations.     

472—Model reactions of nucleotide sorption: Part I. Interaction between adenine nucleotides and interface in the hydrocarbon-water-cetyltrimethyl ammonium bromide system

A study has been made of the binding between nucleotides (ATP, ADP) and other anions (HP₃O₁₀^4?, HP₂O₇^3?, HPO₄^2?, SO₄^2?) on the interface in the heptane-water-cetyltrimethylammonium bromide (CTAB) system. The binding between anions and their complexes with CTAB on the interface was registered by two methods: by change in interphase tension values and by change in the potential jump on the interface. The energies of binding of the above anions on the interface in the presence of CTAB are determined.The data obtained enabled us to assess the energy of binding of a negative charge with the interface (- ΔG ? 14.6 ± 0.7 kJ/unit charge).A model has been suggested for a study of the behaviour of the interface-CTAB-anion system and the conditions for specific nucleotide binding have been chosen.     

Ultrasonic-assisted preparation of novel ternary ZnO/Ag3VO4/Ag2CrO4 nanocomposites and their enhanced visible-light activities in degradation of different pollutants

Novel ternary ZnO/Ag₃VO₄/Ag₂CrO₄ nanocomposites were successfully fabricated via preparation of ZnO/Ag₃VO₄ followed by coupling of it with Ag₂CrO₄ through facile ultrasonic-assisted method. The resultant samples were carefully characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive analysis of X-rays, UV–vis diffuse reflectance spectroscopy, Fourier transform-infrared spectroscopy, and photoluminescence techniques. Photocatalytic activity for degradation of organic dyes, including rhodamine B, methylene blue, and methyl orange was examined under visible-light irradiation. Among the prepared samples, the ternary nanocomposite with 20% of Ag₂CrO₄ demonstrated the superior activity. This nanocomposite showed 10.6, 2.9, and 3.0-folds greater activity compared to ZnO, ZnO/Ag₂CrO₄, and ZnO/Ag₃VO₄, respectively. The enhanced activity was attributed to more harvesting of the visible-light irradiation and efficiently separation of the photogenerated charge carriers in the ternary nanocomposites. To understand efficiently separation of the charge carriers, a plausible diagram was proposed based on formation of tandem n-n heterojunctions.     

Two-Dimensional Layered Metallic VSe2/SWCNTs/rGO Based Ternary Hybrid Materials for High Performance Energy Storage Applications

In this work, the ternary hybrid structure VSe₂/SWCNTs/rGO is reported for supercapacitor applications. The ternary composite exhibits a high specific capacitance of 450 F g⁻¹ in a symmetric cell configuration, with maximum energy density of 131.4 Wh kg⁻¹ and power density of 27.49 kW kg⁻¹. The ternary hybrid also shows a cyclic stability of 91 % after 5000 cycles. Extensive density functional theory (DFT) simulations on the structure as well as on the electronic properties of the binary hybrid structure VSe₂/SWCNTs and the ternary hybrid structure VSe₂/SWCNTs/rGO have been carried out. Due to a synergic effect, there are enhanced density of states near the Fermi level and higher quantum capacitance for the hybrid ternary structure compared to VSe₂/SWCNTs, leading to higher energy and power density for VSe₂/SWCNTs/rGO, supporting our experimental observation. Computed diffusion energy barrier of electrolyte ions (K⁺) predicts that ions move faster in the ternary structure, providing higher charge storage performance.     

Preparation of hierarchical LiNixCoyMnzO2 from solvothermal [NixCoyMnz](OH)2 via regulating the ratio of Ni,Co, and Mn and its excellent properties for lithium-ion battery cathode

The ternary-layered oxide (LiNi_xCo_yMn_zO₂) has become the most promising cathode material for lithium-ion batteries due to the advantages of higher discharge platform, better conductivity, and higher theoretical capacity. The [Ni_xCo_yMn_z](OH)₂ with different ratios of nickel, cobalt, and manganese (NCM) was prepared by solvothermal method, and then ternary cathode material LiNi_xCo_yMn_zO₂ was obtained by mixing lithium and calcining. In this paper, ternary cathode materials with different ratios of NCM were prepared by the solvothermal method. The structure and morphology of the materials were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The effects of the ratio on the electrochemical properties of the materials were investigated by constant current charge and discharge test and electrochemical impedance spectroscopy test. The synthesized lithium-nickel-cobalt-manganese oxide belongs to the hexagonal system and has an α-NaFeO₂ layered structure, which is an R-3m space group. The NCM ternary cathode materials with different morphologies were obtained by changing the ratio of NCM. The sample with NCM ratio of 5:3:2 has a unique sheet-like spherical shape and has the best rate performance.     

PEGylated gold nanorod separation based on aspect ratio: characterization by asymmetric-flow field flow fractionation with UV-Vis detection

The development of highly efficient asymmetric-flow field flow fractionation (A4F) methodology for biocompatible PEGylated gold nanorods (GNR) without the need for surfactants in the mobile phase is presented. We report on the potential of A4F for rapid separation by evaluating the efficiency of functionalized surface coverage in terms of fractionation, retention time (t _R ) shifts, and population analysis. By optimizing the fractionation conditions, we observed that the mechanism of separation for PEGylated GNRs by A4F is the same as that for CTAB stabilized GNRs (i.e., according to their AR) which confirms that the elution mechanism is not dependent on the surface charge of the analytes and/or the membrane. In addition, we demonstrated that A4F can distinguish different surface coverage populations of PEGylated GNRs. The data established that a change in M_w of the functional group and/or surface orientation can be detected and fractionated by A4F. The findings in this study provide the foundation for a complete separation and physicochemical analysis of GNRs and their surface coatings, which can provide accurate and reproducible characterization critical to advancing biomedical research.

Bonding in the ground state and excited states of copper-alkene complexes

The ground state and ¹B₂ excited state of Cu(C₂H₄)⁺ and of CuX(C₂H₄) (X  F, Cl) have been investigated by the Hartree-Fock-Slater (HFS) method. The main metal-ligand interactions in the ground state are ethene π → Cu 4s donation and Cu 3d_π → ethene π^* backdonation, which have comparable contributions to the metal-ligand bond strength. The excitation of CuX(C₂H₄) does not involve an alkene π → metal charge transfer (LMCT), but instead is metal 3d → alkene π^* charge transfer (MLCT) in character. The implications for the photochemistry of olefin-copper(I) complexes are discussed.     

Modeling of the three-phase equilibrium in systems of the type water + nonionic surfactant + alkane

Liquid–liquid equilibria of systems water (A) + C_iE_j surfactant (B) + n-alkane (C) have been modeled by a mass-action law model previously developed and so far successfully applied to a series of binary water + C_iE_j systems and to the ternary system water + C₄E₁ + n-dodecane. These calculations provide the basis for the presented modeling. The aqueous systems give information about the association constants and the χ_AB-parameter of the Flory–Huggins theory and the ternary C₄E₁-system provides universal temperature functions for the χ_AC- and the χ_BC-parameter. The three-phase equilibrium for seven ternary C_iE_j systems (i = 6–12, j = 3–6) has been calculated by fitting one additional parameter for each of both temperature functions to the characteristic “fish-tail” point. The agreement with the experimental data is reasonably well. For systems with very small three-phase areas the results can considerably be improved by individual temperature functions that incorporate the experimental temperature maximum of the “fish” into the parameter fit. Based on the parameters of the system water + C₈E₄ + n-C₈H₁₈ the “fish-shaped” phase diagram of the system water + C₈E₄ + n-C₁₄H₃₀ was predicted reasonably well.