隨著工業和交通的快速發展，許多化工生產過程中產生的工業氣體對周圍環境造成極大污染，也對人類健康造成巨大危害。因此，氣體傳感器在工業和環境監測領域對檢測這些有害氣體起著至關重要的作用。最近，NiPS3奈米片因其1.6 eV的能隙和大的比表面積而被認為是一種潛在的傳感材料。通過計算方法徹底了解NiPS3傳感器的靈敏度和選擇性將有助於我們開發具有更好性能的感測設備。在此背景下，本論文通過密度泛函理論(DFT)，對作為電導式和電阻式傳感器的原始和有缺陷的NiPS3片進行研究。首先，我們研究了六種環境氣體（H2O、CO2、CO、NH3、NO2和NO）在原始和有缺陷的 NiPS3 奈米片上的吸附。我們發現與原始NiPS3片相比，H2O、CO2、NO2和NO分子可以強烈吸附在有缺陷的NiPS3奈米片上。我們還研究了有缺陷的NiPS3奈米片在氣體吸附時的電流-電壓（I-V）曲線，以了解電導和電阻靈敏度的變化。在低偏置電壓下，NO和NO2分子表現出更高的電導靈敏度，這表明有缺陷的NiPS3片可用作檢測NO和NO2氣體的電導式傳感器。然而，當我們施加低偏置電壓時，CO2分子顯示出最大的電阻靈敏度值，表明CO2分子的檢測可以被視為電阻式傳感器。此外，我們還考慮了應變對有缺陷的NiPS3傳感器的吸附強度和恢復時間的影響。我們發現H2O和NO的吸附強度和恢復時間表明對應變條件的敏感性更高。另外，我們的計算顯示當我們在有缺陷的NiPS3奈米片上施加壓縮應變時，可以有效地減少氣體脫附的恢復時間和所需的溫度。基於這些理論結果，我們闡明了氣體與原始與有缺陷的NiPS3奈米片之間的基本相互作用。我們預計NiPS3奈米片上的硫空位可以提供理想的傳感材料，具有合適的能隙和對氣體檢測的更大電導/電阻靈敏度。

With the rapid development of industries and transportation, industrial gases are produced in many chemical production processes, resulting in great pollution to the surrounding environment and huge damage to the health of human beings. Therefore, gas sensors play a vital role in detecting these harmful gases in the industrial and environmental monitoring fields. Recently, NiPS3 nanosheet has been regarded as a potential sensing material owing to its suitable band gap of 1.6 eV and high specific surface area. A thorough understanding of the sensitivity and selectivity of the NiPS3 sensor by computational approach will help us develop these devices with better performance. In this context, we presented computational investigations of the pristine and the defected NiPS3 sheets as conductivity and resistive sensors by density functional theory (DFT) calculations. First, we studied the adsorption of six environmental gases (H2O, CO2, CO, NH3, NO2, and NO) on the pristine and the defected NiPS3 sheets. We found that H2O, CO2, NO2, and NO molecules can strongly adsorb on the defected NiPS3 sheet compared to the pristine NiPS3 sheet. We also explored the current–voltage (I–V) curve of the defected NiPS3 sheet upon the gas’s adsorption to understand the change of conductance and resistance sensitivity. Under the low bias voltage, the NO and NO2 molecules demonstrated higher conductance sensitivity, suggesting that the defected NiPS3 sheet can be used as an electrical conductivity sensor for sensing NO and NO2 gases. Nevertheless, the CO2 molecule showed the largest value of resistance sensitivity when we applied the low bias voltage, indicating that the defected NiPS3 sheet can be considered as a resistive sensor for CO2 molecule. In addition, we considered the strain effects on the adsorption strength and the recovery time for the defected NiPS3 sensor and found that the adsorption strength and recovery time of H2O and NO demonstrates a greater sensitivity to the strain conditions. Besides, our calculations indicated that recovery time and required temperature for the gas desorption can be effectively reduced when we applied compressive strain to the defected NiPS3 sheet. We elucidated the fundamental interaction between the gases and the pristine/defected NiPS3 sheet based on these theoretical results. Therefore, we expect that a sulfur vacancy on the NiPS3 sheet could provide an ideal sensing material with suitable band gap and greater conductance/resistance sensitivity toward these gases detection.

1. Yamazoe, N., Toward Innovations of Gas Sensor Technology. Sensors and Actuators B: Chemical 2005, 108, 2-14.
2. Kohl, D.; Kelleter, J.; Petig, H., Detection of Fires by Gas Sensors. Sensors update 2001, 9, 161-223.
3. Wilson, A. D.; Baietto, M., Applications and Advances in Electronic-Nose Technologies. Sensors 2009, 9, 5099-5148.
4. Dey, A., Semiconductor Metal Oxide Gas Sensors: A Review. Materials Science and Engineering: B 2018, 229, 206-217.
5. Guth, U.; Vonau, W.; Zosel, J., Recent Developments in Electrochemical Sensor Application and Technology—a Review. Measurement Science and Technology 2009, 20, 042002.
6. Ballantine Jr, D.; White, R. M.; Martin, S. J.; Ricco, A. J.; Zellers, E.; Frye, G.; Wohltjen, H., Acoustic Wave Sensors: Theory, Design and Physico-Chemical Applications; Elsevier, 1996.
7. Arshak, K.; Moore, E.; Lyons, G.; Harris, J.; Clifford, S., A Review of Gas Sensors Employed in Electronic Nose Applications. Sensor review 2004.
8. Nazemi, H.; Joseph, A.; Park, J.; Emadi, A., Advanced Micro-and Nano-Gas Sensor Technology: A Review. Sensors 2019, 19, 1285.
9. Lakkis, S.; Younes, R.; Alayli, Y.; Sawan, M., Review of Recent Trends in Gas Sensing Technologies and Their Miniaturization Potential. Sensor Review 2014.
10. Graf, M.; Barrettino, D.; Taschini, S.; Hagleitner, C.; Hierlemann, A.; Baltes, H., Metal Oxide-Based Monolithic Complementary Metal Oxide Semiconductor Gas Sensor Microsystem. Analytical Chemistry 2004, 76, 4437-4445.
11. Kang, J.-g.; Park, J.-S.; Lee, H.-J., Pt-Doped Sno2 Thin Film Based Micro Gas Sensors with High Selectivity to Toluene and Hcho. Sensors and Actuators B: Chemical 2017, 248, 1011-1016.
12. Xing, R.; Du, Y.; Zhao, X.; Zhang, X., Gas Sensor Based on 3-D Wo3 Inverse Opal: Design and Applications. Sensors 2017, 17, 710.
13. Liu, X.; Ma, T.; Pinna, N.; Zhang, J., Two‐Dimensional Nanostructured Materials for Gas Sensing. Advanced Functional Materials 2017, 27, 1702168.
14. Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang, Y.; Dubonos, S. V.; Grigorieva, I. V.; Firsov, A. A., Electric Field Effect in Atomically Thin Carbon Films. science 2004, 306, 666-669.
15. Yoon, H. J.; Yang, J. H.; Zhou, Z.; Yang, S. S.; Cheng, M. M.-C., Carbon Dioxide Gas Sensor Using a Graphene Sheet. Sensors and Actuators B: Chemical 2011, 157, 310-313.
16. Stassen, I.; Dou, J.-H.; Hendon, C.; Dincă, M., Chemiresistive Sensing of Ambient Co2 by an Autogenously Hydrated Cu3 (Hexaiminobenzene) 2 Framework. ACS central Science 2019, 5, 1425-1431.
17. Barzegar, M.; Tiwari, A., On the Performance of Vertical Mos2 Nanoflakes as a Gas Sensor. Vacuum 2019, 167, 90-97.
18. Lee, E.; VahidMohammadi, A.; Prorok, B. C.; Yoon, Y. S.; Beidaghi, M.; Kim, D.-J., Room Temperature Gas Sensing of Two-Dimensional Titanium Carbide (Mxene). ACS applied materials & interfaces 2017, 9, 37184-37190.
19. Wang, F.; Shifa, T. A.; Yu, P.; He, P.; Liu, Y.; Wang, F.; Wang, Z.; Zhan, X.; Lou, X.; Xia, F., New Frontiers on Van Der Waals Layered Metal Phosphorous Trichalcogenides. Advanced Functional Materials 2018, 28, 1802151.
20. Samal, R.; Sanyal, G.; Chakraborty, B.; Rout, C. S., Two-Dimensional Transition Metal Phosphorous Trichalcogenides (MPX3): A Review on Emerging Trends, Current State and Future Perspectives. Journal of Materials Chemistry A 2021, 9, 2560-2591.
21. Wang, J.; Wang, T.; Shi, X.; Wu, J.; Xu, Y.; Ding, X.; Yu, Q.; Zhang, K.; Zhou, P.; Jiang, Z., Nips 3 Nanosheets for Passive Pulse Generation in an Er-Doped Fiber Laser. Journal of Materials Chemistry C 2019, 7, 14625-14631.
22. Jenjeti, R. N.; Kumar, R.; Austeria, M. P.; Sampath, S., Field Effect Transistor Based on Layered Nips 3. Scientific reports 2018, 8, 1-9.
23. Ismail, N.; Madian, M.; El-Meligi, A., Synthesis of Nips3 and Cops and Its Hydrogen Storage Capacity. Journal of alloys and compounds 2014, 588, 573-577.
24. Jenjeti, R. N.; Kumar, R.; Sampath, S., Two-Dimensional, Few-Layer NiPS3 for Flexible Humidity Sensor with High Selectivity. Journal of Materials Chemistry A 2019, 7, 14545-14551.
25. Wang, F.; Shifa, T. A.; He, P.; Cheng, Z.; Chu, J.; Liu, Y.; Wang, Z.; Wang, F.; Wen, Y.; Liang, L., Two-Dimensional Metal Phosphorus Trisulfide Nanosheet with Solar Hydrogen-Evolving Activity. Nano Energy 2017, 40, 673-680.
26. Naumis, G. G.; Barraza-Lopez, S.; Oliva-Leyva, M.; Terrones, H., Electronic and Optical Properties of Strained Graphene and Other Strained 2d Materials: A Review. Reports on Progress in Physics 2017, 80, 096501.
27. Xiang, H.; Xu, B.; Xia, Y.; Yin, J.; Liu, Z., Tunable Electronic Structures in MPX3 (M= Zn, Cd; X= S, Se) Monolayers by Strain Engineering. RSC advances 2016, 6, 89901-89906.
28. Kresse, G.; Furthmüller, J., Efficiency of Ab-Initio Total Energy Calculations for Metals and Semiconductors Using a Plane-Wave Basis Set. Computational materials science 1996, 6, 15-50.
29. Kresse, G.; Furthmüller, J., Efficient Iterative Schemes for Ab Initio Total-Energy Calculations Using a Plane-Wave Basis Set. Physical review B 1996, 54, 11169.
30. Kresse, G.; Hafner, J., Ab Initio Molecular Dynamics for Liquid Metals. Physical Review B 1993, 47, 558.
31. Kresse, G.; Hafner, J., Ab Initio Molecular-Dynamics Simulation of the Liquid-Metal–Amorphous-Semiconductor Transition in Germanium. Physical Review B 1994, 49, 14251.
32. Perdew, J. P.; Yue, W., Accurate and Simple Density Functional for the Electronic Exchange Energy: Generalized Gradient Approximation. Physical review B 1986, 33, 8800.
33. Perdew, J. P.; Burke, K.; Ernzerhof, M., Generalized Gradient Approximation Made Simple. Physical review letters 1996, 77, 3865.
34. Blöchl, P. E., Projector Augmented-Wave Method. Physical review B 1994, 50, 17953.
35. Kresse, G.; Joubert, D., From Ultrasoft Pseudopotentials to the Projector Augmented-Wave Method. Physical review b 1999, 59, 1758.
36. Dudarev, S.; Botton, G.; Savrasov, S.; Humphreys, C.; Sutton, A., Electron-Energy-Loss Spectra and the Structural Stability of Nickel Oxide: An Lsda+ U Study. Physical Review B 1998, 57, 1505.
37. Klimeš, J.; Bowler, D. R.; Michaelides, A., Chemical Accuracy for the Van Der Waals Density Functional. Journal of Physics: Condensed Matter 2009, 22, 022201.
38. Klimeš, J.; Bowler, D. R.; Michaelides, A., Van Der Waals Density Functionals Applied to Solids. Physical Review B 2011, 83, 195131.
39. Sanville, E.; Kenny, S. D.; Smith, R.; Henkelman, G., Improved Grid‐Based Algorithm for Bader Charge Allocation. Journal of computational chemistry 2007, 28, 899-908.
40. Datta, S., Electronic Transport in Mesoscopic Systems; Cambridge university press, 1997.
41. Wildes, A. R.; Simonet, V.; Ressouche, E.; Mcintyre, G. J.; Avdeev, M.; Suard, E.; Kimber, S. A.; Lançon, D.; Pepe, G.; Moubaraki, B., Magnetic Structure of the Quasi-Two-Dimensional Antiferromagnet NiPS3. Physical Review B 2015, 92, 224408.
42. Piacentini, M.; Khumalo, F.; Olson, C.; Anderegg, J.; Lynch, D., Optical Transitions, Xps, Electronic States in NiPS3. Chemical Physics 1982, 65, 289-304.
43. Aghaei, S.; Aasi, A.; Farhangdoust, S.; Panchapakesan, B., Graphene-Like Bc6n Nanosheets Are Potential Candidates for Detection of Volatile Organic Compounds (VOCs) in Human Breath: A Dft Study. Applied Surface Science 2021, 536, 147756.
44. Ghadiri, M.; Ghashghaee, M.; Ghambarian, M., Mn-Doped Black Phosphorene for Ultrasensitive Hydrogen Sulfide Detection: Periodic Dft Calculations. Physical Chemistry Chemical Physics 2020, 22, 15549-15558.