Npj Comput. Mater.: 气体传感材料：吸附响应的第一性原理计算

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Fig.1 | Schematics for calculating the response of 2D gas sensing materials.

来自清华大学燃烧能源中心和车辆学院的张亮副教授团队，提出了一套同时考虑载流子浓度和迁移率的第一性原理计算框架，来计算二维化学电阻型传感材料的响应，并以二维MoS₂为例验证了其准确性。

Fig.2 | NH3 adsorption density on bilayer MoS2 and resultant carrier concentrations of MoS2under varying NH3 concentrations.

Fig.3 | The carrier mobility and scattering rate of bilayer MoS2 under varying NH3concentrations.

理论与实验结果的对比表明，相较于电荷转移方法，该方法可提供更为准确的响应和检测极限（LOD）。此外，他们将载流子浓度和迁移率从电导率中解耦，量化了两者分别对气体总响应的贡献。结果表明，二维MoS₂是一种载流子浓度占主导的气体传感材料，且导致电荷转移方法高估响应或低估LOD的主要原因为该方法通常会高估载流子浓度的变化。这是因为，通过计算得到的从气体分子转移到传感材材中的电荷通常不会全部转化为可自由移动的载流子。相反，它们可能会被界面上的一些特定位点吸收或与空穴重新结合。上述分析显示，尽管电荷转移方法能够对载流子浓度主导的气体传感材料吸附响应（如NH3@MoS2）提供一定程度的定性解释，但该方法并不适用于对这些材料响应的定量估计，尤其是对于那些载流子迁移率主导的材料。该研究为探索新型载流子迁移率主导的传感材料、筛选有前景的气体传感材料以及对传感机理的定量化理解提供了新的机遇。

Fig.4 | The comparison between experimental results and computational predictions.

该文近期发表于npj Computational Materials 10: 138 (2024)，英文标题与摘要如下，点击左下角“阅读原文”可以自由获取论文PDF。

Accurate first-principles simulation for the response of 2D chemiresistive gas sensors

Shuwei Li & Liang Zhang

The realm of chemiresistive gas sensors has witnessed a notable surge in interest in two-dimensional (2D) materials. The advancement of high-performance 2D gas sensing materials necessitates a quantitative theoretical method capable of accurately predicting their response. In this context, we present our first-principles framework for calculating the response of 2D materials, incorporating both carrier concentration and mobility. We showcase our method by applying it to prototype NH3 sensing on 2D MoS2 and comparing the results with prior experiments in the literature. Our approach offers a thorough solution for carrier concentration, taking into account the electronic structure around the Fermi level. In conjunction with the mobility calculation, this enables us to provide a quantitative prediction of the response profile and limit of detection (LOD), yielding a notably improved alignment with prior experimental findings. Further analysis quantifies the contributions of carrier concentration and mobility to the overall response of 2D MoS2 to NH3. We identify that discrepancies in the charge-transfer-based method primarily stem from overestimating carrier concentrations. Our method opens exciting opportunities to explore carrier mobility-dominated sensing materials, facilitates efficient screening of promising gas sensing materials, and quantitative understanding of the sensing mechanism.