BiOBr nanosheets with oxygen vacancies and lattice strain for enhanced photoelectrochemical sensing of doxycycline

Abstract Defects and lattice strain are key to photoelectrochemical (PEC) sensing performance of semiconductors. In this work, BiOBr nanosheets were annealed at different temperatures to form oxygen vacancies (OVs) and relax lattice strain simultaneously. A BiOBr sample annealed at 200 oC exhibited the best photoelectric response because of a synergistic effect between the OV concentration and lattice strain. The sample was screened for the subsequent PEC sensing of a widely used antibiotic of doxycycline (DOC). The fabricated BiOBr sensor had a wide linear detection range from 0.50 μM to 1 mM. The sensitivity was 74.96 nA per decade of concentration and the limit of detection (LOD) was estimated to be 0.14 μM at 3σ/S. The sensor also displayed good selectivity and stability. Additionally, an plausible mechanism responsible for the sensing enhancement was proposed. The work reported here provides a new strategy for optimizing the PEC sensing performance of semiconductor oxides by balancing the OV concentration and lattice strain.