Establishing Interfacial Charge-Transfer Transitions on Ferroelectric Perovskites: An Efficient Route for Photoelectrochemical Bioanalysis

This work presents the concept of establishing interfacial charge-transfer transitions (ICTT) on ferroelectric perovskites for efficient photoelectrochemical (PEC) bioanalysis. The model system was exemplified by using representative lead titanate (PbTiO₃) and an enzyme tandem consisting of the isocitrate dehydrogenase (ICDH) and p-hydroxybenzoate hydroxylase (PHBH). The enzymatic generation of protocatechuic acid (PCA) can coordinate onto the surface of the PbTiO₃ and hence form the ICTT that enables direct ligand-to-metal charge transfer from the highest occupied molecular orbital (HOMO) of PCA to the conduction band (CB) of PbTiO₃ under light irradiation. Due to the ferroelectric polarization induced electric field of PbTiO₃ and the surface polarity of PCA modification, enhanced charge separation of the ICTT contributes to the generation of anodic photocurrent and thus underlies a unique route for detecting the enzymatic activity or its substrate. For dehydrogenase detection, this strategy has better performance than some classical methodologies in terms of high sensitivity and improved selectivity. This work not only features ICTT establishment on ferroelectric perovskites for unique bioanalysis but also provides new insights into the utilization of ferroelectric perovskites for advanced PEC bioanalysis.