Recently, researchers spare no efforts to fabricate desirable vanadium dioxide (VO2) film which provides simultaneously high luminous transmittance and outstanding solar modulation ability, yet progress towards the optimization of one aspect always comes at the expense of the other. Our research devotes to finding a reproducible economic solution-processed strategy for fabricating VO2-SiO2 composite films, with the aim of boosting the performance of both aspects. Compare to VO2 film, an improvement of 18.9% (from 29.6% to 48.5%) in the luminous transmittance as well as an increase of 6.0% (from 9.7% to 15.7%) in solar modulation efficiency is achieved when the molar ratio of Si/V attains 0.8. Based on the effective medium theory, we simulate the optical spectra of the composite films and the best thermochromic property is obtained when the filling factor attains 0.5, which is consistent with the experimental results. Meanwhile, the improvement of chemical stability for the composite film against oxidation has been confirmed. Tungsten is introduced to reduce the phase transition temperature to the ambient temperature, while maintain the thermochromism required for application as smart window. Our research set forth a new avenue in promoting practical applications of VO2-based thermochromic fenestration.

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Polyvinyl alcohol (PVA)-protected silver nanoarchitecture (PVA-Ag nanofilm) on the surface of the glass substrate was prepared by using electrostatic self-assembly at a proper voltage. The two-dimensional morphology of the PVA-Ag nanofilm has been examined by scanning electron microscopy (SEM). The surface-enhanced Raman scattering (SERS) spectra of human serum (HS) on PVA-Ag nanofilms were recorded. The results show that the Raman scattering of HS can be enhanced efficiently based on these PVA-Ag nanofilms. However, it also can be seen that the effect of sodium citrate (SC) acting as anticoagulant on the SERS spectrum of HS is unnegligible, which has not been discussed adequately in the previous reports. To discuss the effect of SC on the SERS spectrum of HS, we have studied the normal Raman spectra of solid SC and the SERS spectra of 1.0×10 −3 mol/l aqueous solution of SC adsorbed on the PVA-Ag nanofilms. Meanwhile, Raman wavenumbers of the SC molecule were calculated by using the method of DFT-B3LYP/6-31G * , and the dominant assignations of the calculated wavenumbers were performed. It was found that the density functional theory (DFT) calculation of SC Raman spectrum matches well with the experimental results. With the perfect reproducibility and high SERS activity, this method will be useful in the development of HS detection methods.

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