Highly enhanced NH3-sensing performance of BC6N monolayer with single vacancy and Stone-Wales defects: A DFT study

Highlights: • Pure BC₆N monolayer cannot be used as high-performance gas sensors. • BC₆N monolayer with single vacancy and Stone-Wales defects are dynamically stable. • Introduction of monovacancies in BC₆N monolayer enhances strongly NH₃-sensing performance. • BC₆N monolayer with MV_C, MV_N, and rippled-SW defects is promising candidates for NH₃ sensors. Searching for suitable NH₃-sensing materials has important scientific significance and application value. Using DFT calculations, the adsorption behaviors, electronic, gas-sensing, and optical properties of NH₃ and other common molecules on the BC₆N monolayer without and with single vacancy (MV) and Stone-Wales (SW) defects were investigated to fully exploit the possibilities of the BC₆N monolayer as a NH₃ gas sensor. Our results showed that the pure BC₆N monolayer has bad gas-sensing performance for NH₃ detection. The BC₆N monolayer with MV_C, MV_N, MV_B, and rippled-SW defects are all dynamically stable. The studies on adsorption behaviors (adsorption energy, geometric structures, and adsorption mode), charge transfer, electron density difference, electronic and optical properties indicate that the BC₆N monolayer with MV_C, MV_N, and rippled-SW defects is promising candidates for NH₃ sensors, indicating the introduction of monovacancies (MV_C, MV_N, and rippled-SW) in BC₆N monolayer can enhance strongly the NH₃-sensing performance.