Jian-Po Zhang

Optical and electrical properties of organic-inorganic composite system

Abstract Anionic phthalocyanine sodium hydrogallium 4,4′,4″,4‴-tetrasulfonated phthalocyanine(GaTsPc) was used to modify the surface of a size-quantized particulate TiO 2 photoelectrode fabricated by electrostatic attraction. The photovoltaic features and interfacial electron transfer of the electrodes were studied by a photoelectrochemical method and surface photovoltage spectroscopy. The results indicate that the light absorption of phthalocyanine monomer makes more contribution to the photovoltaic response in the TiO 2 /GaTsPc composite electrode in spite of obvious aggregation occurring in composite electrode.

THEORETICAL COMPUTATIONAL STUDIES ON ELECTRONIC STRUCTURES, SPECTROSCOPIC PROPERTIES AND NITROGEN HETEROATOM EFFECT OF A SPECIES OF ASYMMETRICAL DIIMINE LIGAND PLATINUM(II) COMPLEXES

Electronic structures and spectroscopic properties of a series of platinum(II) complexes based on the C-linked asymmetrical diimine ligand (2-pyridyl-pyrazole (1), 2-pyridyl-1,2,4-triazole (2), 2-pyridyl-tetrazole (3), 2-pyrazine-pyrazole (4) have been studied by the time-dependent density functional theory calculations with polarizable continuum model. The ground- and excited-state structures were optimized by the density functional theory and single-excitation configuration interaction methods, respectively. The calculated structures and spectroscopic properties are in agreement with the corresponding experimental data. The results of the spectroscopic investigations revealed that the lowest-energy absorptions have1,3metal-to-ligand charge transfer (MLCT)/1,3single ligand centered charge transfer (ILCT) mixing characters. The highest-occupied molecular orbitals (HOMOs) of 1–4 are composed of Pt (dyz) and azole, while the lowest-unoccupied molecular orbitals (LUMOs) are mainly localized upon the pyridyl-azolate ligand (70% on the pyridine segment). From 1 to 3, the molecular orbital (MO) energies of HOMO and LUMO are decreased and the HOMO energies are changed more remarkably. This is caused by that the conjugation of the azolate segment of the ligand are enhanced through introducing more N heteroatoms into this segment. As a result of MO energy change, the lowest-energy absorptions are blue-shifted in the order 1 < 2 < 3. With the replacement of pyridyl by pyrazine, the HOMO energy of 4 is comparable to 1, but the LUMO energy is decreased by 0.8 eV, and the lowest-energy absorptions are red-shifted to 2.36 eV. Otherwise, the phosphorescent emissions of these complexes have the 3MLCT/3ILCT characters, and should originate from the lowest-energy absorptions. The emissions of 1–4 are red-shifted in the order 3 < 2 < 1 < 4. The heteroatom effect is suitable for tuning the spectra of this kind of materials.

Theoretical Studies on Structures and Spectroscopic Properties of Highly Efficient Phosphorescent [Ru(terpy)(phen)X]+ Complexes

The ground and the lowest-lying triplet excited state geometries, electronic structures, and spectroscopic properties of three mixed-ligand Ru(II) complexes [Ru(terpy)(phen)X]+ (terpy=2,2′,6′,2″-terpyridine, phen=1,10-phenanthroline, and X=—C≡CH (1), X=Cl (2), X=CN (3)) were investigated theoretically using the density functional theory method. The ground and excited state geometries have been fully optimized at the B3LYP/LanL2DZ and UB3LYP/LanL2DZ levels, respectively. The absorption and emission spectra of the complexes in CH3CN solutions were calculated by time-dependent density functional theory with the PCM solvent model. The calculated bond lengths of Ru—C, Ru—N, and Ru—Cl in the ground state agree well with the corresponding experimental results. The highest occupied molecular orbital were dominantly localized on the Ru atom and monodentate X ligand for 1 and 2, Ru atom and terpy ligand for 3, while the lowest unoccupied molecular orbital were π* (terpy) type orbital. Therefore, the lowest-energy a...

Hydrothermal synthesis, crystal structure and photoelectric properties of KCuPO4 · 6H2O

Abstract A new double salt of phosphoric acid, KCuPO 4 · 6H 2 O, has been hydrothermally synthesized. Its structure was determined and refined by full-matrix least-squares procedures using automatic diffractometer data to a residual R=0.0628(R w =0.2131). The space group is P2/c with a=6.1303(3)A, b=12.1781(6)A, c=8.9962(2)A, β =105.018(4)°, V=648.68(6)A 3 , and Z=2. The measurement of surface photovoltage as function of wavelength indicates that this new compound can yield obvious photovoltaic response in 550–800 nm visible region and exhibit better photoelectric conversion efficiency.