Hole-conducting mediator for stable Sb2S3-sensitized photoelectrochemical solar cells

Iodide redox (3I(-)/I-3(-)), polysulfide redox (S2-/S-x(2-)), organic redox [TMTU/TMFDS2+: tetramethylthiourea/tetramethylformaminium-bis(trifluoromethanesulfonyl) imide], ferrocene redox (Fc/Fc(+)), nickel redox [Ni(II)/Ni(III)], and cobalt redox [Co(II)/Co(III)] hole conducting electrolytes were systematically investigated to determine their suitability for use in Sb2S3-sensitized photoelectrochemical solar cells. A long-term stability test and UV-visible spectral analyses revealed that Sb2S3-sensitized photoelectrochemical solar cells worked stably with Co(II)(o-phen)(3)(TFSI)(2)/Co (III)(o-phen)(3)(TFSI)(3) [TFSI: bis(trifluoromethanesulfonyl)imide] as the redox mediator.