Surfactant effects on electrochemically durable lead halide perovskite electro-catalysts.

Electrochemically durable perovskite electrodes of nickel foam/TiO/FA(PbGe)I, passivated using various surfactants of tetra--alkyl ammonium halides (alkyl = ethyl, butyl, hexyl, or octyl; halide = I, IBr, Br, BrCl, or Cl), were successfully applied as good electro-catalysts on the counter electrodes in dye-sensitized solar cells (DSSCs). The longer alkyl chain of a surfactant resulted in a higher water contact angle, but poorer film conductivity. Based on the optimal tetra--hexyl ammonium (THA) cation, shrinking the halide radius of THA from I to IBr formed an appropriate amount of FAPbBr nano-crystals covering on the FA(PbGe)I grain surface.