For the relevant properties of pristine and doped (Si, P, Se, Te, As) monolayer WS2 before and after the adsorption of CO, CO2, N2, NO, NO2 and O2, density functional theory (DFT) calculations are made. Calculation results reveal that the monolayer WS2 doped with P and As atoms can be substrate materials for NO and NO2 gas sensors. However, after the subsequent CDD and ELF calculations, it is found that P-doped monolayer WS2 adsorbs NO and NO2 in a chemical way, while As-doped monolayer WS2 adsorbs NO and NO2 in a physical way. Also, the charge transfer between As-doped monolayer WS2 and NO is relatively small and not easily detected. Besides, As-doped monolayer WS2 system exhibits greater differences in optical properties (the imaginary part of reflectivity and dielectric function) before and after the adsorption of NO2 gas than before and after adsorption of NO gas. These differences in optical properties assist sensor devices in making gas adsorption-related judgments. Through the analysis of the recovery time, DOS and PDOS, As-doped monolayer WS2 is also verified to be a promising NO2 sensing material, whose recovery time is calculated to be as short as 0.169 ms at 300 K.

中文翻译：

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基于 DFT 方法的 Asd 单层 WS2 上大气污染物 NO2 的理论研究


对于吸附 CO、CO2、N2、NO、NO2 和 O2 前后原始和掺杂 （Si、P、Se、Te、As） 单层 WS2 的相关性质，进行了密度泛函理论 （DFT） 计算。计算结果表明，掺杂 P 和 As 原子的单分子层 WS2 可以成为 NO 和 NO2 气体传感器的衬底材料。然而，经过随后的 CDD 和 ELF 计算，发现 P 掺杂单分子层 WS2 以化学方式吸附 NO 和 NO2，而砷掺杂单分子层 WS2 以物理方式吸附 NO 和 NO2。此外，As掺杂单层WS2和NO之间的电荷转移相对较小，不易被检测到。此外，As掺杂单层WS2体系在吸附NO2气体前后的光学性质（反射率和介电函数的虚部）比吸附NO气体前后表现出更大的差异。这些光学特性的差异有助于传感器设备做出与气体吸附相关的判断。通过对恢复时间、DOS 和 PDOS 的分析，As掺杂单层 WS2 也被验证为一种很有前途的 NO2 传感材料，其在 300 K 下的恢复时间短至 0.169 ms。