关键词: 染料敏化太阳能电池, 电纺, 纳米纤维, 微孔膜, 电导率

The electrospinning technique provides a simple, cost-effective approach for producing polymeric and inorganic nano?bers with structures that vary with the processing parameters. In this paper, the polymer/TiO₂ hybrid nanofibers microporous membranes were prepared from a polymer solution containing titanium (IV) butoxide (TBT) by electrospinning technique. The as-spun nanofibers microporous membranes were placed in air for 5 h to allow complete hydrolysis. The morphology of the microporous membranes was observed using electron scanning microscopy (SEM) under vacuum condition. The uptake and porosity of microporous membranes were investigated by weighting method before and after soaking electrolyte. The ionic conductivity of the microporous membranes was measured using the complex impedance technique. The blocking cell of stainless steel/microporous membranes/stainless steel was used at 1—10⁵ Hz frequency range at 25 ℃. The AC amplitude was 5 mV. The TiO₂ electrode was obtained by spreading titania paste (P25) on the conducting glass substrate using a doctor blade technique. The dye-sensitized solar cells (DSSCs) devices were fabricated based on the microporous membrane electrolyte by sandwiching a slice of the polymer/TiO₂ hybrid nanofibers microporous membrane between a dye-sensitized TiO₂ electrode and a Pt counter electrode. The edges of the cell were sealed with narrow strips of Surlyn hot melt. The morphology and three-dimensional structure of polymer/TiO₂ hybrid nanofibers microporous membranes did not markedly change after absorbing liquid electrolyte, which indicated that the introduction of TiO₂ into polymer nanofibers could improve the mechanical properties of the nanofibers. These also made the polymer/TiO₂ hybrid nanofibers microporous membranes possess high uptake and porosity. The TiO₂ content in hybrid nanofibers was about 50 wt% according to the TG results. The wetting and diffusion properties of hybrid nanofibers microporous membranes to liquid electrolyte were improved due to the incorporation of TiO₂. The ionic conductivities of PVP/TiO₂, PAN/TiO₂ hybrid nanofibers microporous membranes quasi-solid electrolyte could reach 2.81 mS·cm^-1 and 2.62 mS·cm^-1, respectively, which were close to those of liquid electrolytes. The overall conversion efficiencies of quasi-solid DSSCs with N719 dye based on PVP/TiO₂, PAN/TiO₂ hybrid nanofibers microporous membranes quasi-solid electrolyte reached 7.79% and 7.97%, respectively, which exceeded over 90% of the liquid electrolyte. Meanwhile, the fabricated DSSCs showed good long-term stability.

Key words: dye sensitized solar cells, electrospinning, nanofiber, microporous membrane, conductivity