Er-doped BiFeO3 solid solution for 1 ppb acetone detection with high humidity resistance

Poor humidity resistance and insufficient ultralow detection capability remain unsolved issues for metal oxide semiconductor-based gas sensors. Herein, we prepared a range of Er 3+ -doped BiFeO 3 solid solutions for acetone gas sensing. Among them, Bi 0.92 Er 0.08 FeO 3 gave a 550% increase in gas response and a detection limit of down to 1 parts-per-billion for acetone vapor. Moreover, its gas response curve kept nearly unchanged across varying humidity, showing strong humidity independence. The high dielectric constant, large lattice distortion, and domain wall conductivity generated by the non-centrosymmetric structure prove beneficial for acetone sensing performance. This work presents a rational approach to designing high-performance gas sensors through tuning dielectric constant and crystal structure.