Photoelectrochemical Bioanalysis Platform of Gold Nanoparticles Equipped Perovskite Bi<sub>4</sub>NbO<sub>8</sub>Cl

We have developed sensitive photoelectrochemical (PEC) detection of cysteine using the gold nanoparticles (Au NPs) equipped perovskite Bi<sub>4</sub>NbO<sub>8</sub>Cl heterostructure. The Bi<sub>4</sub>NbO<sub>8</sub>Cl was prepared by a solid-state reaction, and the Au NPs/Bi<sub>4</sub>NbO<sub>8</sub>Cl electrode was made through the electrostatic layer-by-layer self-assembly technique. The Au NPs/Bi<sub>4</sub>NbO<sub>8</sub>Cl electrode provided much enhanced photocurrent with a great increase compared to the bare Bi<sub>4</sub>NbO<sub>8</sub>Cl electrode and allowed for the plasmon-enhanced PEC detection of cysteine with good performance. It demonstrated rapid response, high stability, wide linear detection range and certain selectivity, implying its great promise in its application. Therefore, the Au NPs/Bi<sub>4</sub>NbO<sub>8</sub>Cl heterostructure has provided a promising platform for the development of PEC bioanalysis. More generally, these findings offered an insight into the exploitation of perovskite materials for PEC bioanalytical purposes.