Tunable Volatile Organic Compounds Sensor by Using Thiolated Ligand Conjugation on MoS sub(2)

One of the most important issues in the development of gas sensors for breath analysis is the fabrication of gas sensor arrays that possess different responses for recognizing patterns for volatile organic compounds (VOCs). Here, we develop a high-performance chemiresistor with a tunable sensor response and high sensitivity for representative VOC groups by using molybdenum disulfide (MoS sub(2)) and by conjugating a thiolated ligand (mercaptoundecanoic acid (MUA)) to MoS sub(2) surface. Primitive and MUA-conjugated MoS sub(2) sensing channels exhibit distinctly different sensor responses toward VOCs. In particular, the primitive MoS sub(2) sensor presents positive responses for oxygen-functionalized VOCs, while the MUA-conjugated MoS sub(2) sensor presents negative responses for the same analytes. Such characteristic sensor responses demonstrate that ligand conjugation successfully adds functionality to a MoS sub(2) matrix. Thus, this will be a promising approach to constructing a versatile sensor array, by conjugating a wide variety of thiolated ligands on the MoS sub(2) surface. Furthermore, these MoS sub(2) sensors in this study exhibit high sensitivity to representative VOCs down to a concentration of 1 ppm. This approach to fabricating a tunable and sensitive VOC sensor may lead to a valuable real-world application for lung cancer diagnosis by breath analysis. Keywords: Chemiresistor; molybdenum disulfides; MoS sub(2); volatile organic compound; VOC; gas sensor