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A di-vanadium-substituted Lindqvist-type polyoxometalate [Cu(C12H8N2)2]2[V2W4O19]·4H2O (1) was hydrothermally synthesized and characterized structurally by single crystal X-ray diffraction analysis. X-ray photoelectron spectroscopy and energy disperse spectroscopy tests further prove the existence of vanadium. Ultraviolet photoelectron spectroscopy and density functional theoretical studies indicate that the energy level of 1 matches well with the conduction band of the TiO2. Furthermore, considering the semiconductor-like nature of 1 and the introduction of transition metal element Cu synchronously extends the absorption to the visible region, which should also be beneficial to the photovoltaic device performance. 1-Doped TiO2 composites (denoted as 1@TiO2) have been successfully fabricated by a simple sol–gel method, and introduced into the dye-sensitized solar cells (DSSCs) as co-sensitizers in N719-sensitized photoanodes by mixing 1@TiO2 with P25 nanoparticles with different weight ratios to enhance the photoelectric conversion efficiency. The investigations show that the DSSC assembled with 1@TiO2/19P25 photoanode has the best performance and the overall improvement of the efficiency is 21.6% compared with pure P25. Furthermore, the electrochemical impedance spectroscopy and open-circuit voltage decay investigations show that the cosensitization of 1 and N719 can promote electron transfer and restrain charge recombinations in the DSSCs, resulting in a longer electron lifetime. [ABSTRACT FROM AUTHOR]

Nearly monodisperse CdS hierarchical hollow nanospheres have been synthesized on a large scale through a Na3cit-assisted solution route. The hollow structure has an application as a drug carrier and the CdS building blocks have fluorescent capabilities. The T1-agent, Gd–DTPA, is then conjugated to the CdS hierarchical hollow nanospheres through N-ethyl-N′-[3-(dimethylamino)propyl]carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling chemistry using surface absorbed Na3cit molecules as an intermedium. Thus, multifunctional magnetic-fluorescent CdS@Gd–DTPA hierarchical hollow nanospheres are formed, which combine magnetic resonance imaging (MRI), fluorescent imaging and drug delivery into one system. The as-prepared products are characterized in detail by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Fourier transform infrared spectrometry. The room temperature photoluminescent spectra and T1-weighted maps of the obtained CdS@Gd–DTPA are carried out using a fluorescence spectrophotometer and a 3 T MRI scanner, respectively. The results indicate that the as-prepared product is a potential candidate for simultaneous disease diagnosis and therapy by combining the multiplexing imaging capability. [ABSTRACT FROM AUTHOR]