Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Flexible Gas Sensors for Monitoring Volatile Organic Compounds" By Yen-Yu Chen Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Lia A. Stanciu ABSTRACT Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are considered as a new class of sensing materials because of their flexible layered structure, high specific surface area, and good semiconducting properties. A gas sensor capable of operating at room temperature is appealing because it requires a simple fabrication process and low power consumption. Herein, a review of various sensing materials, metal-oxide semiconductors, carbon-based materials, and TMDCs, for the detecting features of different life-affecting and environment-impacting gases, including volatile organic compounds (VOCs), inorganic gases (NH3 and NO2), and ethylene, will be presented. Then, the fabrication methods of TMDCs, particularly 2D MoS2 (layered nanoflake), will be introduced. These reviews suggest that (a) LPE is one of most promising cost-effective methods to synthesize 2D TMDC gas-sensing materials in a mass-production manner and (b) surface modification is required for TMDCs to detect gases effectively at room temperature. Indeed, preliminary research results indicate that the gas sensors made of Au-decorated LPE-MoS2 exhibit superior ability to sense extremely low concentrations of VOCs at room temperature. A series of LPE-TMDCs will be further studied for the development of high-performance, room-temperature gas sensors. Date: Tuesday, December 5, 2017 Time: 1:30 P.M. Place: ARMS 1109