Sensing Mechanism of H2O, NH3, and O2 on the Stability-Improved Cs2Pb(SCN)2Br2 Surface: A Quantum Dynamics Investigation

Although the perovskite sensing materials have shown high sensitivity and ideal selectivity toward neutral, oxidative, or reductive gases, their structural instability hampers the practical application. To exploit perovskite-based gas-sensing materials with improved stability and decent sensitivity, three adsorption complexes of H2O, NH3, and O-2 on the Cs2Pb-(SCN)(2)Br-2 surface are built by doping Br- and Cs+ in the parent (CH3NH3)(2)Pb(SCN)(2)I-2 structure and submitted to quantum dynamics simulations. Changes in the semiconductor material geometric structures during these dynamic processes are analyzed and adsorption ability and charge transfer between Cs2Pb-(SCN)(2)Br-2 and the gas molecules are explored so as to further establish a correlation between the geometrical structure variations and the charge transfer. By comparing with the previous CH3NH3PbI3 and (CH3NH3)(2)Pb(SCN)(2)I-2 adsorption systems, we propose the key factors that enhance the stability of perovskite structures in different atmospheres. The current work is expected to provide clues for developing innovative perovskite sensing materials or for constructing reasonable sensing mechanisms.

Automated summary

This study established adsorption complexes of H2O, NH3, and O-2 on the Cs2Pb-(SCN)(2)Br-2 surface through quantum dynamics simulations, exploring the stability of perovskite structures in different atmospheres and the impact of geometric structure changes on charge transfer. The research provides insights for developing innovative perovskite sensing materials and constructing reasonable sensing mechanisms.