Donor-Acceptor Competition via Halide Vacancy Filling for Oxygen Detection of High Sensitivity and Stability by All-Inorganic Perovskite Films

Oxygen detection by organic-inorganic halide perovskites (OIHPs) has demonstrated advantages in operating temperature, response time, and reversibility over traditional materials. However, OIHPs can only sense O-2 in light and the unavoidable O-2 exposure during detection easily induces the degradation of OIHPs. The trade-off between sensitivity and stability makes the OIHP-based oxygen sensors impractical. By replacing organic groups with Cs, the compact films of all-inorganic halide perovskites (AIHPs) that can adsorb O-2 at grain boundaries in dark are developed. AIHPs show conductance increase of 1875.5% from 1 x 10(-5) to 700 Torr of O-2 pressure, associated with full reversibility and long-term stability. Combining experiments and modeling, this work reveals the donor-acceptor competition via halide vacancy filling leading to the modulation of carrier concentration and mobility. This work offers understandings on oxygen sensing by perovskite materials and paves the way for further optimization of AIHPs as promising oxygen sensors with high sensitivity and stability.

Automated summary

This study developed compact films of all-inorganic halide perovskites (AIHPs) by replacing organic groups with Cs, which can adsorb oxygen at grain boundaries in dark with high sensitivity and stability. The experiments and modeling revealed the donor-acceptor competition via halide vacancy filling, leading to the modulation of carrier concentration and mobility. These findings provide insights into oxygen sensing by perovskite materials and lay the foundation for further optimization of AIHPs as promising oxygen sensors.