Cobalt titanate-titania composite oxide films have been grown on FTO-coated glass substrates using a single-source heterometallic complex [Co2Ti4(μ-O)6(TFA)8(THF)6]·THF () which was obtained in quantitative yield from the reaction of diacetatocobalt(ii) tetrahydrate, tetraisopropoxytitanium(iv), and trifluoroacetic acid from a tetrahydrofuran solution. Physicochemical investigations of complex have been carried out by melting point, FT-IR, thermogravimetric and single-crystal X-ray diffraction analyses. CoTiO3-TiO2 films composed of spherical objects of various sizes have been grown from by aerosol-assisted chemical vapor deposition at different temperatures of 500, 550 and 600 °C. Thin films characterized by XRD, Raman and X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis have been explored for electrochemical detection of dopamine (DA). The cyclic voltammetry with the CoTiO3-TiO2 electrode showed a DA oxidation peak at +0.215 V while linear sweep voltammetry displayed a detection limit (LoD) of 0.083 μM and a linear concentration range of 20-300 μM for DA. Thus, the CoTiO3-TiO2 electrode is a potential candidate for the sensitive and selective detection of DA.
Core-shell rutile TiO2@β-In2S3 and modified V-TiO2@β-In2S3 were synthesized to develop bilayer systems to uphold charge transport via an effective and stable interface. Morphological studies revealed that β-In2S3 was deposited homogeneously on V-TiO2 as compared to unmodified TiO2 nanorod arrays. X-ray photoelectron spectroscopy (XPS) and electron energy loss spectrometry studies verified the presence of various oxidation states of vanadium in rutile TiO2 and the vanadium surface was utilized for broadening the charge collection centers in host substrate layer and hole quencher window. Subsequently, X-ray diffraction, high-resolution transmission electron microscopy, and Raman spectra confirmed the rutile phases of TiO2 and modified V-TiO2 along with the phases of crystalline β-In2S3. XPS valence band study explored the interaction of valence band quazi Fermi levels of β-In2S3 with the conduction band quazi Fermi levels of modified V-TiO2 for enhanced charge collection at the interface. Photoelectrochemical studies show that the photocurrent density of V-TiO2@β-In2S3 is 1.42 mA/cm(2) (1.5AM illumination). Also, the frequency window for TiO2 was broadened by the vanadium modification in rutile TiO2 nanorod arrays, and the lifetime of the charge carrier and stability of the interface in V-TiO2@β-In2S3 were enhanced compared to the unmodified TiO2@β-In2S3. These findings highlight the significance of modifications in host substrates and interfaces, which have profound implications on interphase stability, photocatalysis and solar-fuel-based devices.
Symmetrical and unsymmetrical dithiocarbamato pyridine solvated and non-solvated complexes of indium(III) with the general formula [In(S2CNRR')3]·n(py) [where py = pyridine; R,R' = Cy, n = 2 (1); R,R' = (i)Pr, n = 1.5 (2); NRR' = Pip, n = 0.5 (3) and R = Bz, R' = Me, n = 0 (4)] have been synthesized. The compositions, structures and properties of these complexes have been studied by means of microanalysis, IR and (1)H-NMR spectroscopy, X-ray single crystal and thermogravimetric (TG/DTG) analyses. The applicability of these complexes as single source precursors (SSPs) for the deposition of β-In2S3 thin films on fluorine-doped SnO2 (FTO) coated conducting glass substrates by aerosol-assisted chemical vapour deposition (AACVD) at temperatures of 300, 350 and 400 °C is studied. All films have been characterized by powder X-ray diffraction (PXRD) and energy dispersive X-ray analysis (EDX) for the detection of phase and stoichiometry of the deposit. Scanning electron microscopy (SEM) studies reveal that precursors (1)-(4), irrespective of different metal ligand design, generate comparable morphologies of β-In2S3 thin films at different temperatures. Direct band gap energies of 2.2 eV have been estimated from the UV-vis spectroscopy for the β-In2S3 films fabricated from precursors (1) and (4). The photoelectrochemical (PEC) properties of β-In2S3 were confirmed by recording the current-voltage plots under light and dark conditions. The plots showed anodic photocurrent densities of 1.25 and 0.65 mA cm(-2) at 0.23 V vs. Ag/AgCl for the β-In2S3 films made at 400 and 350 °C from the precursors (1) and (4), respectively. The photoelectrochemical performance indicates that the newly synthesised precursors are highly useful in fabricating β-In2S3 electrodes for solar energy harvesting and optoelectronic application.