2D Heterointerface‐Mediated Chemisorption Pathways Enable Selective Dual‐Gas Detection at Room Temperature
Vishnu G. Nath, Kenneth Lobo, Shalini Tomar, Vijaya Kumar Gangaiah, Kalpak Ghosh, Sharma S. R. K. C. Yamijala, Seung‐Cheol Lee, Satadeep Bhattacharjee, H. S. S. Ramakrishna Matte, Angappane SubramanianABSTRACT
Heterointerfacial modulation in 2D transition metal dichalcogenides (TMDs) offers a unique route to introduce a portfolio of fascinating properties, allowing layered materials to manifest multi‐dimensional features for advanced device applications. Herein, functionally distinct heterostructures of 2H‐MoS 2 are engineered via controlled Ar and O 2 plasma treatments, resulting in 1T/2H‐MoS 2 and MoO 3 /2H‐MoS interfaces, respectively, which in turn facilitate selective gas chemisorption. The tailored heterointerfaces reshape local electronic and surface energy landscapes of 2H‐MoS 2 , where electron transfer from metallic 1T domains strengthens n‐type conductivity, while hole injection from MoO 3 reinforces p‐type behavior. Experimental measurements, supported by density functional theory, indicate that carrier‐density modulation, together with the formation of favorable adsorption sites, governs the chemisorption behavior of oxidizing NO 2 and reducing NH3 molecules. The 1T/2H‐MoS 2 and MoO 3 /2H‐MoS 2 sensors selectively detect NO 2 and NH 3 with minimum detection limits of 165 and 138 ppb, respectively, at room temperature. The practical applicability of the sensors, demonstrated by fabricating a portable sensor array, showcases effective NO 2 detection in vehicular exhaust and NH 3 sensing in spoiled meat, underscoring their potential for environmental and food‐safety monitoring. By strategically engineering heterointerfaces, this study translates tunable TMD properties into chemisorption‐controlled gas discrimination.