Photocurrent enhancement of interlocked LB film dye layers in a p-CuSCN sensitised photoelectrochemical cell

Dye sensitised photoelectrochemical (PEC) cells based on Cu/p-CuSCN/LB films have been studied with mixed Langmuir Blodgett (LB) films as the dye layer. The effects of mixed layers were investigated in detail by observing the changes of optical absorption and photocurrent in a PEC cell configuration. Enhancements in both optical absorption and photocurrent were found when a mixture of octadecyl methylviolet–C₁₈ (M–C₁₈) and dioctadecyl rhodamine (C₁₈–R–C₁₈) were deposited using the LB technique on p-CuSCN wide band gap semiconductor. The maximum photocurrent quantum efficiency of the PEC cell reached ≈36% in KI (10⁻² M)+I₂ (10⁻⁴ M) electrolyte solution when mixed LB films were used as the dye layer. Photocurrent enhancement is believed to be the enhancement of light absorption of the dye layers due to the interlocking of M–C₁₈ between the double C₁₈ chains of rhodamine.