N3-sensitized TiO2 films: in situ proton exchange toward open-circuit photovoltage enhancement.

摘要: Protons of N3, cis-bis(thiocyanato)bis(2,2‘-bipyridyl-4,4‘-dicarboxylic acid)ruthenium(II), were in situ exchanged on N3-loaded TiO2 films with alkali-metal, tetrabutylammonium, and guanidinium cations. This simple strategy improved the open-circuit photovoltage (Voc) significantly, resulting enhancement power conversion efficiency by 10−25%. Electrochemical impedance spectra revealed that proton exchange film suppressed charge recombination between injected electrons I3- ions electrolyte, which, together negative shift conduction band edge for TiO2, may account remarkably increased Voc upon N3.