Gold Nanoparticle-Attached Perovskite Cs₃Bi₂Br₉ QDs/BiOBr Heterostructures for Photoelectrochemical Biosensing

A photoelectrochemical (PEC) sensing platform based on gold nanoparticle (AuNP)-attached perovskite Cs3Bi2Br9 QDs/BiOBr heterostructures was developed to set up a photocathodic analysis platform for sensitive detection of hydrogen peroxide (H2O2). A series of detailed analyses demonstrated that the Cs3Bi2Br9 QDs/BiOBr heterostructures with high photoelectric activity were successfully prepared by water treatment producing BiOBr-encapsulated Cs3Bi2Br9 QDs. The decoration of AuNPs can initiate a surface plasmon resonance enhancement effect to further effectively improve the PEC performance. The resulting AuNPs/Cs3Bi2Br9 QDs/BiOBr-modified photoelectrode presents efficient photoelectrochemical performance for H2O2 sensing in a wide linear detection range from 0.002 to 200 μM with a very low detection limit down to 0.89 nM. Meanwhile, it exhibits excellent performance of good stability, favorable specificity, and acceptable reproducibility. Moreover, the promising platform is capable of monitoring H2O2 released from living tumorigenic cells, indicating its promising potential in biological applications. This work highlights a useful strategy toward simple and easy photoelectrochemical biosensing of photoelectrically active molecules for further utilization, which should be valuable for revealing the potential of lead-free perovskites and their heterostructures for advanced PEC biosensing applications.