Deposition of polyaniline via molecular self-assembly on TiO2 and its uses as a sensitiser in solid-state solar cells

Volatile solvent free quasi-solid solar cells were fabricated using acid-doped polyaniline (PANI) covalently grafted on surface-modified nanocrystalline TiO2 substrates via self assembled monolayer (SAM) of silane-bearing aniline compound (C6H5NHC3H6Si(OMe)3) (SAM) and investigated their photovoltaic performances with different additives. PANI was able to sensitize TiO2 efficiently in the presence of SAM. Introduction of ionic liquid 1-ethyl-3-methylimidazolium bis(trifluroromethyl)sulfonylamid and LiTf2N enhanced the photocurrent of TiO2/PANI/Au cell by more than two-fold. The cell treated with 1-methyl-3-n-hexylimidazolium iodide delivered a photocurrent of ∼450 μA cm−2 with photovoltage of ∼565 mV, giving an efficiency of ∼0.12% (FF=0.47).