电化学法制备硅纳米线

Silicon nanowires were synthesized from nanometer silicon dioxide powder under potentiostatic electrolysis at -1.20 V (vs Pt reference) for 4 h in molten CaCl₂ at 900 ℃. The morphology, structure and chemical composition of the samples prepared by electroreduction method were characterized by field-emission scanning electron microscopy(FE-SEM), High-resolution transmission electron microscopy(HRTEM) coupled with electron energy dispersive spectroscopy(EDS), laser Raman and X-ray diffraction(XRD). The results revealed that silicon nanowires were crystalline with a diamond cubic structure, the diameter was distributed from 50 nm to 80 nm and the length was generally several micrometers. The formed nanowires basically consisted of silicon monocrystalline and amorphous oxide sheath.     

熔盐电解法制备硅纳米线的过程机理

采用FESEM、XRD和EDS分析了纳米二氧化硅烧结片在900℃的CaCl2熔盐中浸泡后结构和组成的变化,结果表明,由于纳米尺寸效应和CaCl2熔盐对二氧化硅的熔融(软化)具有助熔作用,纳米二氧化硅烧结片在900℃的CaCl2熔盐中由固态转变为熔融或半熔融态。根据对900℃的CaCl2熔盐中-1.2V恒电位电解不同时间电极片上反应区的结构和组成分析结果,提出了纳米二氧化硅电极片的硅/熔融二氧化硅/熔盐三相界面沿极片径向方向均匀推进的电解还原过程。通过对900℃的CaCl2熔盐中-1.2V恒电位电解5和15min电解产物的形貌、结构和成份分析,提出了硅纳米线在熔盐中的电化学成核与生长机理。     

Synthesis and Plasmon‐Induced Charge‐Transfer Properties of Monodisperse Gold‐Doped Titania Microspheres

Functional spheres : Monodisperse gold‐doped titania spheres with tunable sizes under high concentration of titanium precursor have been synthesized by introducing trace amounts of chloroauric acid into the reaction system. Surface photovoltage, surface photocurrent, and transient photovoltage measurements (see figure) of annealed samples reveal that gold nanodots can act as both electron acceptors and donors under the illumination of different wavelengths of light.

     

Revealing the Charge‐Transfer Interactions in Self‐Assembled Organic Cocrystals: Two‐Dimensional Photonic Applications

A new crystal of a charge‐transfer (CT) complex was prepared through supramolecular assembly and it has unique two‐dimensional (2D) morphology. The CT nature of the ground and excited states of this new Bpe‐TCNB cocrystal (BTC) were confirmed by electron spin resonance measurements, spectroscopic studies, and theoretical calculations, thus providing a comprehensive understanding of the CT interactions in organic donor–acceptor systems. And the lowest CT₁ excitons are responsible for the efficient photoluminescence (Φ_PL=19 %), which can actively propagate in individual 2D BTCs without anisotropy, thus implying that the optical waveguide property of the crystal is not related to the molecular stacking structure. This unique 2D CT cocrystal exhibits potential for use in functional photonic devices in the next‐generation optoelectronic communications.     

Symmetry‐Breaking Charge‐Transfer Chromophore Interactions Supported by Carbon Nanodots

Carbon dots (CDs) and their derivatives are useful platforms for studying electron‐donor/acceptor interactions and dynamics therein. Herein, we couple amorphous CDs with phthalocyanines (Pcs) that act as electron donors with a large extended π‐surface and intense absorption across the visible range of the solar spectrum. Investigations of the intercomponent interactions by means of steady‐state and pump‐probe transient absorption spectroscopy reveal symmetry‐breaking charge transfer/separation and recombination dynamics within pairs of phthalocyanines. The CDs facilitate the electronic interactions between the phthalocyanines. Thus, our findings suggest that CDs could be used to support electronic couplings in multichromophoric systems and further increase their applicability in organic electronics, photonics, and artificial photosynthesis.     

Quantum Dots Arrangement and Energy Transfer Control via Charge‐Transfer Complex Achieved on Poly(Phenylene Ethynylene)/Schizophyllan Nanowires

Assemblies of organic and inorganic compounds in the nanoscale region have contributed to the development of novel functional materials toward future applications, including sensors and opto‐electronics. We succeed in fabricating hybrid nanowires composed of a conjugated polymer and semiconductor quantum dots (QDs) by a supramolecular assembly technique. The 1‐D fashion of the nanowire structure is obtained by the polymer wrapping of cationic poly(phenylene ethynylene) (PPE) with helix‐forming polysaccharide schizophyllan (SPG). The electrostatic interaction between cationic PPE and anionic QDs affords the nanowires decorated with QDs. Upon addition of an acceptor molecule, tetranitrofluorenone (TNF), the charge‐transfer (CT) complex between PPE and TNF is formed, resulting in energy transfer from the QDs to PPE arising from the induced spectral overlap. Furthermore, the employment of the conjugated polymer allows highly sensitive quenching of the QD’s emission by raising the transmission efficiency to the CT complexed electron deficient sites along the polymer backbone.     

Increasing the Efficacy of Seproxetine as an Antidepressant Using Charge–Transfer Complexes

The charge transfer interactions between the seproxetine (SRX) donor and π-electron acceptors [picric acid (PA), dinitrobenzene (DNB), p-nitrobenzoic acid (p-NBA), 2,6-dichloroquinone-4-chloroimide (DCQ), 2,6-dibromoquinone-4-chloroimide (DBQ), and 7,7′,8,8′-tetracyanoquinodi methane (TCNQ)] were studied in a liquid medium, and the solid form was isolated and characterized. The spectrophotometric analysis confirmed that the charge–transfer interactions between the electrons of the donor and acceptors were 1:1 (SRX: π-acceptor). To study the comparative interactions between SRX and the other π-electron acceptors, molecular docking calculations were performed between SRX and the charge transfer (CT) complexes against three receptors (serotonin, dopamine, and TrkB kinase receptor). According to molecular docking, the CT complex [(SRX)(TCNQ)] binds with all three receptors more efficiently than SRX alone, and [(SRX)(TCNQ)]-dopamine (CTcD) has the highest binding energy value. The results of AutoDock Vina revealed that the molecular dynamics simulation of the 100 ns run revealed that both the SRX-dopamine and CTcD complexes had a stable conformation; however, the CTcD complex was more stable. The optimized structure of the CT complexes was obtained using density functional theory (B-3LYP/6-311G++) and was compared.     

Supramolecular Assemblies by Charge‐Transfer Interactions between Donor and Acceptor Chromophores

We have collated various supramolecular designs that utilize organic donor–acceptor CT complexation to generate noncovalently co‐assembled structures including fibrillar gels, micelles, vesicles, nanotubes, foldamers, conformationally restricted macromolecules, and liquid crystalline phases. Possibly inspired by nature, chemists have extensively used hydrogen bonding as a tool for supramolecular assemblies of a diverse range of abiotic building blocks. As a structural motif, CT complexes can be compared to hydrogen‐bonded complexes in its directional nature and complementarities. Additional advantages of CT interactions include wider solvent tolerance and easy spectroscopic probing. Nevertheless the major limitation is their low association constant. This article shows different strategies have evolved over the years to overcome this drawback by reinforcing the CT interactions with auxiliary noncovalent forces without hampering the alternate stacking mode. Emerging reports on promising CT complexes in organic electronics are intimately related to various supramolecular designs that one can postulate based on donor–acceptor CT interactions.     

Creation of Ternary Multicomponent Crystals by Exploitation of Charge‐Transfer Interactions

Four new ternary crystalline molecular complexes have been synthesised from a common 3,5‐dinitrobenzoic acid (3,5‐dnda) and 4,4′‐bipyridine (bipy) pairing with a series of amino‐substituted aromatic compounds (4‐aminobenzoic acid (4‐aba), 4‐(N,N‐dimethylamino)benzoic acid (4‐dmaba), 4‐aminosalicylic acid (4‐asa) and sulfanilamide (saa)). The ternary crystals were created through the application of complementary charge transfer and hydrogen‐bonding interactions. For these systems a dimer was created through a charge‐transfer interaction between two of the components, while hydrogen bonding between the third molecule and this dimer completed the construction of the ternary co‐crystal. All resulting structures display the same acid ??? pyridine interaction between 3,5‐dnba and bipy. However, changing the third component causes the proton of this bond to shift from neutral OH ??? N to a salt form, O^? ??? HN⁺, as the nature of the group hydrogen bonding to the carboxylic acid was changed. This highlights the role of the crystal environment on the level of proton transfer and the utility of ternary systems for the study of this process.     

Adsorption of I2 by Macrocyclic Polyazadithiophenolato Complexes Mediated by Charge‐Transfer Interactions

The macrocyclic complex [Ni₂(L)(OAc)]ClO₄ ( 1 ) adsorbs up to 17 molar equivalents (>270 wt %) of iodine, although it does not exhibit permanent porosity. Vibrational spectroscopic and crystallographic studies reveal that two I₂ molecules are captured by means of thiophenolate→I₂ charge‐transfer interactions, which enable the diffusion and sorption of further I₂ molecules in a polyiodide‐like network. The efficient sorption and desorption characteristics make this material suitable for accommodation, sensing, and slow release of I₂.