Intercalation of tetrathiafulvalene in vanadium pentoxide gels

Tetrathiafulvalene (TTF) is readily and irreversibly intercalated by vanadium oxide xerogel (V₂O₅ 1.6 H₂O) in a mixed ethanol/water dispersion medium. The resulting material (TTF_x V₂O₅ with x < 1.8) is an ill-organized, insoluble solid, which contains a large amount of strongly bound water molecules. An XPS analysis shows that an important fraction (up to ～ 25% of the vanadium ions are in the V(IV) state. There is some indirect spectroscopic evidence that this material is a significantly better electronic conductor than the parent xerogel.     

Electrodeposition and characterization of Cu2O thin films using sodium thiosulfate as an additive for photovoltaic solar cells

Cuprous oxide(Cu_2 O) thin films have been grown by electrodeposition technique onto ITO-coated glass substrates from aqueous copper acetate solutions with addition of sodium thiosulfate at 60 ℃. The effects of sodium thiosulfate on the electrochemical deposition of Cu20 films were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were obtained at-0.58 V vs. SCE and characterized by X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), and optical, photoelectrochemical and electrical measurements. X-ray diffraction results indicated that the synthesized Cu20 films had a pure cubic phase with a marked preferential orientation peak along(200) plane and with lattice constants a = b = c = 0.425 nm. FTIR results confirmed the presence of Cu_2 O films at peak 634 cm~(-1) SEM images of Cu_2 O films showed a better compactness and spherical-shaped composition. Optical properties of Cu20 films reveal a high optical transmission(80%) and high absorption coefficient(α 10~4 cm~(-1)) in visiblelight region. The optical energy band gap was found to be 2.103 eV. Photoelectrochemical measurements indicated that Cu20 films had n-type semiconductor conduction, which confirmed by Hall Effect measurements.Electrical properties of Cu20 films showed a low electrical resistivity of 61.30 Ω·cm~(-1), carrier concentration of-4.94 × 10~(15)cm~(-3) and mobility of 20.61 cm~2· V~(-1)·s~(-1).The obtained Cu_2 O thin films with suitable properties are promising semiconductor material for fabrication of photovoltaic solar cells.