Acetone sensing with parts-per-billion limit of detection using a BiFeO_3-based solid solution sensor at the morphotropic phase boundary

摘要

An unsolved yet important issue related to chemiresistive sensors is the lack of ultralow detection capability, i.e., ppb-level detection. Here, we propose a novel strategy to further improve gas sensor performance by introducing morphotropic phase boundaries that have a homogeneous chemical composition but inhomogeneous structures to regulate the band structure and interfaces. The Bi_(1-x)La_xFeO_3 samples located at the morphotropic phase boundary have good selectivity for acetone and showed better gas sensitivity than undoped samples. It is worth noting that the morphotropic phase boundary phase Bi_(0.9)La_(0.1)FeO_3 exhibited ultralow concentration detection of 50 ppb acetone. The mechanism is that the morphotropic phase boundary phase provides a more efficient carrier and variation in hole accumulation layer. This work provides an alternative strategy for designing high-performance sensors in addition to traditional chemical and physical modifications.