In the pursuit of developing fast and reliable gas sensors, a new ternary oxide semiconductor, a bismuth oxyiodide (BiOI)-based sensing material, has been reported with desirable adsorption energy, short recovery time, and high sensitivity and selectivity for detecting nitrogen oxide mixtures (NOx, typically NO and NO2). The structural, electronic, and transport properties of both (001) and (012) planes of BiOI surfaces upon the adsorption of six environmentally relevant gases (NO, NO2, SO2, SO3, O2, and H2O) are systematically explored using a combination of density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods. The results indicate that BiOI (001) exhibits weak interaction with these gases, with the highest adsorption energy observed for NO. In contrast, the BiOI (012) surface shows enhanced adsorption stability for these gases, particularly acceptable strong adsorption to NO2, indicating its promising capability for detecting these gases with high specificity. Moreover, it demonstrates the most intense chemisorption for SO3, suggesting it to be a reliable SO3 adsorbent/cleaner. The obtained transport characteristics, including current-voltage (I-V) and resistance-voltage (R-V) curves, further highlight the higher selectivity of the BiOI (001) device towards NO and the BiOI (012) device towards NO2 against the other gases. Furthermore, the transmission spectra analyses reveal that the BiOI-based sensor can electrically discriminate the target gas molecules from other considered gas molecules. Besides, the practical application possibilities of both orientations are explored by estimating their recovery time, and the results show that the BiOI sensor has excellent recovery times at room temperature (NO/BiOI (001) = 0.158 ns, and NO2/BiOI (012) = 3.89 s), highlighting its potential as an ideal reversible gas-sensing material for detecting NOx gases.

中文翻译：

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碘氧化铋作为高效室温氮氧化物气体传感器：表面取向对传感性能的作用


为了开发快速可靠的气体传感器，一种新型三元氧化物半导体，一种基于碘化铋（BiOI）的传感材料，已被报道具有理想的吸附能、短的恢复时间以及高灵敏度和选择性，可用于检测氮氧化物混合物（NOx，通常为 NO 和 NO2）。通过结合以下方法，系统地探讨了 BiOI 表面的 (001) 和 (012) 平面在吸附六种环境相关气体（NO、NO2、SO2、SO3、O2 和 H2O）时的结构、电子和输运特性。密度泛函理论（DFT）和非平衡格林函数（NEGF）方法。结果表明，BiOI (001) 与这些气体表现出弱相互作用，NO 的吸附能最高。相比之下，BiOI（012）表面对这些气体表现出增强的吸附稳定性，特别是对NO2的强吸附，表明其具有高特异性检测这些气体的良好能力。此外，它对 SO3 具有最强的化学吸附作用，表明它是一种可靠的 SO3 吸附剂/清洁剂。获得的传输特性，包括电流-电压（IV）和电阻-电压（RV）曲线，进一步凸显了BiOI（001）器件对NO和BiOI（012）器件对NO2相对于其他气体的更高选择性。此外，透射光谱分析表明，基于 BiOI 的传感器可以将目标气体分子与其他考虑的气体分子区分开来。此外，通过估计其恢复时间来探索这两个方向的实际应用可能性，结果表明BiOI传感器在室温下具有优异的恢复时间（NO/BiOI（001）= 0。158 ns，NO2/BiOI (012) = 3.89 s)，凸显了其作为检测 NOx 气体的理想可逆气敏材料的潜力。