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

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A photoelectrochemical (PEC) sensing platform based on gold nanoparticle (AuNP)-attached perovskite Cs 3 Bi 2 Br 9 QDs/BiOBr heterostructures was developed to set up a photocathodic analysis platform for sensitive detection of hydrogen peroxide (H 2 O 2 ). A series of detailed analyses demonstrated that the Cs 3 Bi 2 Br 9 QDs/BiOBr heterostructures with high photoelectric activity were successfully prepared by water treatment producing BiOBr-encapsulated Cs 3 Bi 2 Br 9 QDs. The decoration of AuNPs can initiate a surface plasmon resonance enhancement effect to further effectively improve the PEC performance. The resulting AuNPs/Cs 3 Bi 2 Br 9 QDs/BiOBr-modified photoelectrode presents efficient photoelectrochemical performance for H 2 O 2 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 H 2 O 2 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.