  Metal halide perovskites (MHPs) have attracted significant attention owing to
their simple manufacturing process and unique optoelectronic properties. Their
reversible electrical or optical properties changes in response to oxidizing or
reducing environments make them prospective materials for gas detection
technologies. Despite advancements in perovskite-based sensor research, the
mechanisms behind perovskite-gas interactions, vital for sensor performance,
are still unexclusive. This work presents the first evaluation of the sensing
performance and long-term stability of MHPs, considering factors such as halide
composition variation and Mn doping levels. The research reveals a clear
correlation between halide composition and sensing behavior, with Br-rich
sensors displaying a p-type response to O3 gas, while Cl-based counterparts
exhibit an n-type sensing behavior. Notably, Mn-doping significantly enhances
the O3 sensing performance by facilitating the gas adsorption process, as
supported by both atomistic simulations and experimental evidence. Long-term
evaluation of the sensors provides valuable insights into evolving sensing
behaviors, highlighting the impact of dynamic instabilities over time. Overall,
this research offers insights into optimal halide combination and Mn-doping
levels, representing a significant step forward in engineering room temperature
perovskite-based gas sensors that are not only low-cost and high-performing but
also durable, marking a new era in sensor technology.
