AI 中文总结
本研究通过DFT-NEGF方法揭示层状BiOI的气体选择性由费米能级附近传输通道演化决定，建立了以输运为核心的选择性框架，为低功耗偏压可调气体传感器设计提供机理解释。
AI 中文摘要
明确吸附热力学与电荷输运调制的相互作用，对于合理设计低功耗、偏压可调的气体传感器至关重要。本文通过将密度泛函理论（DFT）与非平衡格林函数（NEGF）输运计算相结合，对层状氧碘化铋（BiOI）的气体选择性开展了全面的第一性原理研究，系统考察了其对NO₂、NH₃、CO₂及代表性挥发性有机化合物的吸附与偏压依赖输运响应。NH₃和NO₂呈现强化学吸附与局域电子扰动，而CO₂则通过弱物理吸附相互作用，表明仅吸附强度无法决定传感性能；费米能级附近传输通道的演化才是传感响应的控制因素。偏压依赖计算揭示了电可调的灵敏度层级：弱吸附的CO₂虽电荷转移极少，却能保留导电通路并表现出显著的低偏压灵敏度。恢复时间分析进一步凸显了强吸附物种在输运调制与可逆性之间的权衡。这些结果为层状BiOI建立了以输运为核心的选择性框架，为环境条件下电场控制气体传感提供了机理解释。
英文摘要
Understanding the interplay between adsorption energetics and charge-transport modulation is essential for the rational design of low-power and bias-tunable gas sensors. Here, we present a comprehensive first-principles study of gas selectivity in layered bismuth oxyiodide (BiOI) by integrating density functional theory with nonequilibrium Green's function transport calculations. The adsorption and bias-dependent transport responses toward NO2, NH3, CO2, and representative volatile organic compounds are systematically examined. While NH3 and NO2 exhibit strong chemisorption and localized electronic perturbations, CO2 interacts through weak physisorption, demonstrating that adsorption strength alone does not determine sensing performance. Instead, the evolution of transmission channels near the Fermi level governs the sensing response. Bias-dependent calculations reveal an electrically tunable sensitivity hierarchy, in which weakly adsorbed CO2 preserves conductive pathways and exhibits pronounced low-bias sensitivity despite minimal charge transfer. Recovery-time analysis further highlights the trade-off between transport modulation and reversibility for strongly adsorbed species. These results establish a transport-centered selectivity framework for layered BiOI and provide mechanistic insight into electric-field-controlled gas sensing under ambient conditions.
Comments23 pages, 7 Figures
