R.S. Wang

D5hC50X10: Saturn-like fullerene derivatives (X=F, Cl, Br)

Based on the recently reported D5hC50, the geometries and stabilities of its Saturn-like derivatives C50X10 (X=F, Cl, Br) have been investigated by DFT method. Compared with C50, the equatorial carbon atoms in C50X10 have been saturated by halogens and change to sp3 hybridization to release the large angle strain. Because the equatorial carbon atoms have been taken out of the π system by the halogens “ring,” the C50X10 system has been split into two well-delocalized conjugated annulene subunits, and then the electronic stabilization has been enhanced.

Syntheses, characterization and conductivity of polyaniline doped with H5SiM11VO40(M=Mo,W)

Abstract Polyaniline (PANI) doped with vanadium-containing silicotungstic/molybdic acid have been prepared in a one-step chemical reaction. The polymers were characterised by elemental analysis, IR, XRD, The thermal stability and the conductive property of doped PANI were determined,

Study on EL emission region of polymer thin film in PPV LED

In this paper, the intensity ratios I( λ 1 = 515 nm ) /λ 2 = 550 nm ) of both electroluminescence ( EL ) and photoluminescence ( PL) spectra of poly( phenylene vinylene) (PPV) thin film in the same PPV light-emitting diode (LED) are measured in order to discuss the EL emission dominant region. In the EL spectrum, the ratio I(λ 1 )/I 1 (λ 2 ) decreased from 1,35 to 1.25, when the bias voltage increased from 4 to 12 V. In the PL spectrum, the ratios I 1 (λ 1 ) /I 1 (λ 2 ) and I 2 (λ 1 )/I 2 (λ 2 ) (here I I and I 2 denote the intensities emitting from the indium-tin oxide (ITO) glass side and the opposite side, respectively) approach 1.5 and 1.3, separately. Based on these results, it is deduced that the emission dominant region of EL of PPV thin film in a single-layer PPV LED is close to the top electrode and apart from that of PL.

Nonlinear optical properties for pyridines and stilbazoles adducted by borane

Nonlinear optical (NLO) properties of Me 2 N-4-C 5 H 4 N, MeO-4-C 6 H 4 -CH=CH-C 5 H 4 N, Me 2 N-4-C 6 H 4 -C≡C-C 5 H 4 N and their Lewis acidic borane adductions were studied by using quantum chemical AM1/Finite Field (FF) method. Calculational results indicated that NLO properties of this kind of compounds were improved substantially due to adduction by Lewis acidic borane.

Synthesis of poly(phenylenesulfidephenylenamine) by self-polycondensation of methyl-(4-anilinophenyl) sulfide with antimony pentachloride

Abstract Pory(phenylenesulfidephenylenamine)(PPSA), an alternating copolymer and the hybrid structure of poly(phenylene sulfide)(PPS) and polyaniline(PAn), was synthesized by self-polycondensation of methyl-(4-anilino-phenyl) sulfide with antimony pentachloride and by the acid-induced self-polycondensation of methyl-(4-anilino-phenyl) sulfoxide.

Interactions of Li, Ca, and Al with aromatic carbon materials: An ab initio study

The interactions of benzene (C6H6), naphthalene (C10H8), and perinaphthene (C13H9) with metal atoms (Li, Ca, and Al) were studied using second-order Møller-Plesset perturbation theory. By analyzing the frontier molecular orbitals, geometric structures, binding energies, and charge transfers, it was found that these metal atoms can bond strongly with C13H9, but can only bond weakly with C6H6 and C10H8. The bonding nature between a metal atom and C13H9 at their ground state depends significantly on the valence orbital of the metal atom and the pi-bonding distribution of the aromatic hydrocarbons. The spindly shaped 3p valence orbital of an Al atom results in the deviation of the adsorption site to the edge of C13H9, whereas the ball-shaped 2s/4s valence orbitals of a Li and a Ca atom facilitate their overlap with the second lowest unoccupied molecular orbital of C13H9. Further, Hartree-Fock and density-functional theory methods were demonstrated generally to be unreliable in describing the interactions of metal atoms with these pi systems.

Ab initio research on third-order nonlinear optical properties of linear complexes [M(I)(PH3)2]+(M=Cu, Ag, Au)

Geometry of linear complexes [M(I)(PH 3 ) 2 ] + (M=Cu, Ag, Au) were optimized at different basis set levels adopting ab initio HF and DFT methods of quantum chemistry. The third-order NLO coefficients γ were calculated with FF/HF method. The values y of [M(I)(PH 3 ) 2 ] + (M=Cu, Ag, Au) are 10596.6538, 14649.9410 and 1190.8090a.u. respectively with the basis set of 6-31+G(d) for P and H and the basis set of LANL2DZ for Au by ab initio HF method. The results show the rule of γ[Ag(I)(PH 3 ) 2 ] > γ[Au(I)(PH 3 ) 2 ] + > γ[Cu(I)(PH 3 ) 2 ] + at the different basis set levels.

Quantum chemical studies on intercalation of lithium into polyacene

The structure and properties of Li-doped polyacenic semiconductor (PAS) material have been investigated, Quantum Chemical methods ab initio STO-3G were used to calculate electronic properties of PAS doped with lithium. The semiempirical MO method AM1 was used to optimize the geometric parameters of PAS. The theoretical results showed that the doped lithium was neither in metallic nor ionic state in deeply doped PAS (C 2 Li). The intercalated lithium formed polycenter bonds with carbon atoms, and made the interlayer distance of two parallel polyacenic rings decrease. On the other hand, the total energy of Li-doped PAS system decreased, and made the doped state stable. The theoretical results are in good agreements with the experiment.

The modulation of electronic and optical properties of OXD-X through introduction of the electron-withdrawing groups: a DFT study.

A comparative study using density functional theory (DFT) on the molecular structure, electronic structure and relative properties of 1,3,4-oxadiazole dimers 1,3-bis[2-(4-methylphenyl)-1,3,4-oxadiazol-5-yl]benzene (OXD-X) and its derivatives with alkoxy substituents -O(CH(2))(n-1)CH(3) (OXD-An, n=1, 2) and electron-withdrawing substituents -CN (OXD-C), -CF(3) (OXD-TFM), -NO(2) (OXD-N) added at meta-substitution in the phenyl ring are presented. The ground state structures of the title complexes are optimized at B3LYP/6-31G level of theory. In addition, the time dependent density functional theory (TDDFT) method is applied to calculate the absorption and emission spectra of the derivatives based on the ground state geometries. Comparing with the alkoxy substituents, the results show that the electron-withdrawing substituents have remarkable influences on the energy levels of the frontier molecular orbitals, the spectra and the transition compositions. Especially, -NO(2) group plays the prominent role and the fluorine improves the energy level of LUMO further. The experimental absorption wavelengths for OXD-X, OXD-A3 and OXD-A7 are well reproduced by the TDDFT technique. Moreover the absorption wavelengths and the transition compositions can be effectively adjusted through introducing electro-withdrawing groups in the phenyl ring. The reorganization energies for hole and electron are smaller than that of typical hole and electron transport materials.

Effect of doping ZnCl2 on the structure and properties of carbonaceous material

In this paper, we studied the effect of doping ZnCl 2 on the structure and properties of the product prepared from pyrolyzing pheolic resin. The results show that ZnCl 2 can make the particals of the pyrolytic products uniform. Moreover, the aperture, pore volume and specific surface area can be controlled. If the pyrolytic product is used as electrode material, its reversible charge and discharge capacity can reach 870 mA h/g.