Photoelectrochemical chiral sensing on the basis of TiO2–metal complex hybrid film

A new photoelectrochemical chiral sensor was developed in this study, which was achieved through the combination of Langmuir–Blodgett and self-assembly techniques to cast a monolayer of chiral metal complex Λ-[Os(phen)3]2+ onto a single layer TiO2 film on an indium tin oxide (ITO) substrate. When being applied for photoelectrochemical sensing of binaphthol isomers, the as-prepared hybrid film exhibited a much higher chiral selectivity than the ITO/clay/Λ-[Os(phen)3]2+ film reported earlier. The experimental detection limit is about 20 μM. The great enhancement is because TiO2 provides a better charge separation, which facilitates the electron transfer reaction of those excited Os(II)*. For small peptide derivatives of 5-fluorouracil, the ITO/TiO2/Λ-[Os(phen)3]2+ film yielded a chiral selectivity of 1.5.