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Fluorinating ??a??Extended Molecular Acceptors Yields Highly Connected Crystal Structures and Low Reorganization Energies for Efficient Solar Cells
摘要： The synthesis and characterization of new semiconducting materials is essential for developing high-efficiency organic solar cells. Here, the synthesis, physiochemical properties, thin film morphology, and photovoltaic response of ITN-F4 and ITzN-F4, the first indacenodithienothiophene nonfullerene acceptors that combine π-extension and fluorination, are reported. The neat acceptors and bulk-heterojunction blend films with fluorinated donor polymer poly{[4,8-bis[5-(2-ethylhexyl)-4-fluoro-2-thienyl]benzo[1,2-b:4,5-b′]-dithiophene-2,6-diyl]-alt-[2,5-thiophenediyl[5,7-bis(2-ethylhexyl)-4,8-dioxo-4H,8H-benzo[1,2-c:4,5-c′]dithiophene-1,3-diyl]]} (PBDB-TF, also known as PM6) are investigated using a battery of techniques, including single crystal X-ray diffraction, fs transient absorption spectroscopy (fsTA), photovoltaic response, space-charge-limited current transport, impedance spectroscopy, grazing incidence wide angle X-ray scattering, and density functional theory level computation. ITN-F4 and ITzN-F4 are found to provide power conversion efficiencies greater and internal reorganization energies less than their non-π-extended and non-fluorinated counterparts when paired with PBDB-TF. Additionally, ITN-F4 and ITzN-F4 exhibit favorable bulk-heterojunction relevant single crystal packing architectures. fsTA reveals that both ITN-F4 and ITzN-F4 undergo ultrafast hole transfer (<300 fs) in films with PBDB-TF, despite excimer state formation in both the neat and blend films. Taken together and in comparison to related structures, these results demonstrate that combined fluorination and π-extension synergistically promote crystallographic π-face-to-face packing, increase crystallinity, reduce internal reorganization energies, increase interplanar π–π electronic coupling, and increase power conversion efficiency.
关键词： impedance spectroscopy,organic solar cells,crystal structures,femtosecond transient absorption spectroscopy,computational chemistry
更新于2025-09-23 15:21:01
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Synthesis, crystal structure analysis, spectral characterization and nonlinear optical exploration of potent thiosemicarbazones based compounds: A DFT refine experimental study
摘要： The thiosemicarbazones have exciting biological and nonlinear optical (NLO) applications. The present study reports detail experimental and computational studies of three novel ferrocene-substituted thiosemicarbazones: (E/Z)-4-(4-chlorobenzyl)-1-(1-ferrocenyl-ethyl)thiosemicarbazone (2) and (E/Z)-4-benzyl-1-(1-ferrocenylethyl)thiosemicarbazones (1) and (E/Z)-4-(2-bromo benzyl)-1-(1-ferrocenylethyl)thiosemicarbazone (3). These compounds were synthesized and resolved into their single crystal structures for the estimation of unit cells, space groups, bond angles and bond lengths. Chemical structures of 1–3 were further characterized spectroscopically employing nuclear magnetic resonance technique (1H NMR), infrared (FT-IR), mass and UV–Visible studies. Computational studies of 1–3 were performed using density functional theory (DFT) tools at M06 level of theory and 6–31 + G(d,p) basis set combination to gain the optimized geometry. A good correlation was found between experimental SC-XRD structures and DFT optimized geometries. Electronic properties including natural bond orbital (NBO) analysis, frontier molecular orbitals (FMOs) analysis, spectroscopic FT-IR data and NLO properties were calculated using same M06/6–31 + G(d,p) level of theory. NBO analysis confirmed the formation of charge separation state due to successful migration of electrons from donor to acceptor unit through π-bridge. Global reactivity parameters were estimated using energies of FMOs which described that 1–3 are chemically hard and stable molecules. Vertical electronic transition states were calculated using time-dependent DFT (TDDFT) at same level of theory. NLO properties of 1–3 were computed 5.77, 3.48 and 8.93 times greater than the standard urea molecule respectively. Two-state model confirmed the potential of synthesized molecules as NLO candidates.
关键词： Frontier molecular orbital,Ferrocene-substituted thiosemicarbazones,Spectroscopic data,Crystal structures,Non-linear optical properties,Density functional theory
更新于2025-09-23 15:21:01
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Six 1D/2D Zinc(II) coordination complexes constructed based on semirigid Bis(dimethylbenzimidazole) ligand and different carboxylates: Syntheses, structures, and photoluminescence properties
摘要： A series of zinc(II) coordination complexes, formulated as {[Zn(dbim)1.5(m-H2adica)]n·2H2O}n (1), [Zn(dbim)(H2adi)]n (2), [Zn(dbim)(m-H2bdc)]n (3), [Zn0.5(dbim)0.5(p-H2bdc)0.5]n (4), [Zn(dbim)(H2sdba)]n (5) and [Zn(dbim)0.5(H2atda)]n (6) (dbim = 1-(4-((2,5-dimethyl-3aH-benzo[d]imidazol-1(7aH)-yl)methyl)benzyl)-3a,7a-dihydro-2,5-dimethyl-1H-benzo[d]imidazole, m-H2adica = 1,3-adamantanedicarboxylic acid, H2adi = adipic acid, m-H2bdc = 1,3-benzenedicarboxylic acid, p-H2bdc = 1,4-benzenedicarboxylic acid, H2sdba = 4,4’-sulfonyldibenzoic acid, H2atda = 1,3-adamantanediacetic acid), have been obtained by hydrothermal reactions. Complex 1 features a 1D step-like chain. Complex 2, 3 and 4 exhibits a 4-connected 2D topology with a point symbol of 44·62, severally, while complex 5 possesses a 4-connected 2D topology with the point symbol of (3·43·52)(44·62). Complex 6 is a 1D chain structure. Additionally, complexes 1-6 present different photoluminescence behaviors in the solid state.
关键词： Semirigid ligand,Photoluminescence,Coordination complex,Crystal structures
更新于2025-09-23 15:21:01
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High-Brightness Low-Divergence Tapered Lasers with a Narrow Taper Angle
摘要： High-brightness tapered lasers with photonic crystal structures are designed and fabricated. A narrow taper angle is designed for the tapered section. The device delivers an output power of 3.3 W and a maximum wall-plug efficiency of 43%. The vertical beam divergence is around 11° at different currents. Nearly diffraction-limited beam qualities for the vertical and lateral directions are obtained. The lateral beam quality factor ?? 2 is below 2.5 and the vertical ?? 2 value is around 1.5 across the whole operating current range. The maximum brightness is 85 MW·cm?2sr?1. When the current is above 3.3 A, the brightness is still above 80 MW·cm?2sr?1.
关键词： photonic crystal structures,tapered lasers,High-brightness,brightness,beam quality
更新于2025-09-23 15:19:57
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Fundamental EM‐Wave Absorber Materials
摘要： In this chapter, in order to obtain basic knowledge of carbon materials and ferrite materials, which are typical EM-wave-absorbing materials, their respective characteristics are examined, especially from the viewpoint of molecular and crystal structures. The Jaumann absorber in early stage of the EM-wave absorber was composed of overlaying the material dispersed carbonyl iron to rubber, the resistive sheet, and the dielectric plate, as described in Chapter 1. In this way, since the absorber was invented, carbon-based materials have been mainly used as EM-wave-absorbing materials. On the other hand, copper–zinc-based soft ferrite was invented in 1930 in Japan. However, the nature of this kind of soft ferrite as an EM-wave absorber was unknown for a long time. Magnetic materials typi?ed by ferrite, metallic resistors, and carbon materials used as resistive ?lms are applied to EM-wave absorbers, and they have changed little to this day.
关键词： molecular and crystal structures,EM-wave absorbers,ferrite materials,carbon materials
更新于2025-09-19 17:13:59
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The optical and luminescence properties of Zn1-xGdxO (0≤x≤0.07) quantum dots synthesized via tetraethyl orthosilicate assisted colloidal regime for laser diodes application potential
摘要： Here, we report about Zn1-xGdxO (0≤x≤0.09) semiconductor quantum dots synthesized via tetraethyl orthosilicate assisted colloidal regime for first time. The X-ray diffraction disclosed that the introduction of Gd ions in Zn sites of ZnO did not affect its hexagonal phase. The transmission electron microscopy divulged that the Gd ions caused an increasing of the particle size of Zn1-xGdxO QDs from 3 nm to 18 nm. The EDAX spectra inspected the stoichiometry and high purity of the synthesized Zn1-xGdxO QDs. The doping of ZnO QDs by Gd ions gives rise to a red shifting of the absorption and emission optical spectra. The doping of ZnO QDs by Gd ions instigates a reduction of the ZnO band gap from 3.3 to 2.8 eV. The doping of ZnO QDs by Gd ions improves the luminescence intensity, reduces the spectral width and suppresses the crystal defects. The quantum yield improved from 31% to 94%. These outstanding behaviors give rise to develop prohibitive superiority laser diode from the nanocrystalline Zn1-xGdxO semiconductor quantum dot.
关键词： Quantum yield,Optical absorption,Luminescence,Crystal structures,Quantum dot
更新于2025-09-16 10:30:52
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Molecular Packing and Solid-state Fluorescence of Conjugated Compounds of Carbazole-acrylonitrile Derivatives
摘要： In this review paper, have been investigated three novel crystal structures of three molecules with carbazole substituents as the electron-donor group. These molecules, 2-(phenyl)-3-(N-ethyl-(3'-carbazolyl))acrylonitrile (I), 2-(3''-pyridyl)-3-(N-ethyl-(3'-carbazolyl))acrylonitrile (II), and 2-(4-pyridyl)-3-(N-ethyl-(3′-carbazolyl))acrylonitrile (III) in their structure, possess the electron-donor carbazole moiety, a -CN group attached to the double bond, and a phenyl or a pyridine function at the meta- or para-position. It was revealed with the help of single crystal diffraction X-ray analysis that there exists no difference in the crystal system, because all the compounds were crystallized in monoclinic system with space group P21/c. For determining the effect of the position of the nitrogen atom substitution on the crystal properties, has been analyzed and contrasted the molecular packing in a single crystal with that of other previously reported carbazole derivatives. The double bond bearing N-ethylcarbazole,–CN, phenyl or pyridine groups was observed to impart sufficient polarity in order to show slipped π-stacking aggregation in the solid state, affecting the compounds in the solid state and consequently affecting their fluorescence properties. The substitution at the para position was reported to exhibit more multiple C-H...π interactions as well as an interesting and unexpected short contact distance between adjacent N...N molecules those brought a conformational change resulting in an edge-to-face alignment in the molecules and affecting the best relative photoluminescence efficiency of the sample.
关键词： crystal structures,aggregation,cyano-substituted,Acrylonitrile derivatives,N-carbazole-acrylonitriles photophysical properties,TD-DFT calculations,pyridine derivatives
更新于2025-09-11 14:12:44
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Fundamentals of Electroceramics (Materials, Devices, and Applications) || Binding Forces in Solids and Essential Elements of Crystallography
摘要： In this chapter, we will study how the solids are held together in a structure that can be either polycrystalline or single crystal, how solids are classified based on their governing binding forces, the relationship between structures and the properties they acquire when subjected to an external agent such as an electric or a magnetic field, and, finally, how these properties help engineers and scientists develop devices and their applications. We will also study the nature and properties of single crystals and how their unique properties help us in understanding their importance to science and technology.
关键词： Dielectric Materials,Crystal Structures,Symmetry Elements,Crystallography,Binding Forces
更新于2025-09-09 09:28:46