Carbon nanospheres bridging in perovskite quantum dots/BiOBr: An efficient heterojunction for high-performance photoelectrochemical sensing of deoxynivalenol

Semiconductor-conductor-semiconductor (SCS) heterojunctions with cascade-type energy-level configurations hold great promise in improving the photoelectric conversion efficiency for photoelectrochemical (PEC) sensing. However, the existing SCS heterostructures were restricted by the incidental Coulomb blockade effect, high cost and the complicated preparation procedure. Hence, we induced methylamine bromide perovskite quantum dots-decorated carbon nanospheres (PQDs@CNSs) ensemble to boost the photoelectric activity of bismuth oxybromide (BiOBr) by creating indirect SCS Z-scheme heterojunctions. PQDs@CNSs@BiOBr ternary composites demonstrated substantially higher photocurrent response compared to individual PQDs@CNSs or BiOBr. Moreover, the stability of PQDs materials was greatly promoted through this design. Further combing with immune recognition, highly selective and ultra-sensitive quantitative detection of a kind of mycotoxin, deoxynivalenol (DON) as a food contaminant, was realized. The detection of limit was calculated to be 34.3 pg/mL. Satisfactory recoveries of DON in corn, as well as wheat samples, indicated the practicability of the as-proposed PEC sensors. This facile approach may provide new ideas for the preparation of carbon-based photoactivity semiconductors with desired PEC sensing performance in food safety field.