Effect of proton numbers of phosphate-based co-adsorbents on the photovoltaic performance of dye-sensitized solar cells
- 萨本栋－已发表论文 
Four kinds of small molecules with different proton numbers including phenylphosphonic acid (PPA), diphenylphosphinic acid (DPPA), phosphoric acid triethyl ester (PATEE), and phosphorical acid tributyl ester (PATBE) were employed as co-adsorbents of dye sensitized solar cell (DSC). They were innovatively pre-adsorbed onto the nanocrystalline TiO2 surface before dye molecule sensitization, which were detected from X-ray photoelectron spectrum (XPS). Combined with UV-vis absorption analysis, it was found the co-adsorbents got to bind with TiO2 more and more easily by increasing proton numbers, which in turn made dye loading amount get smaller and smaller. The as-prepared photoanodes were fabricated into solar cells, yielding impressively enhanced short-circuit current and cell efficiency except PPA which decreased the dye loading amount dramatically. The enhancement of charge recombination resistance and electron lifetime analyzed from EIS results revealed that the more prominent photovoltaic performance improvement with fewer protons was resulted by the more efficient inhibition of recombination between electrons in the conduction band of TiO2 and the oxidized species in the electrolyte. Besides, regarding from the charge transport resistance, fewer protons are favorable for the negative shift of the conduction band level of TiO2 and thus larger open-circuit yielding. (C) 2013 Elsevier Ltd. All rights reserved.