UC Riverside

One-dimensional nanostructures, such as nanowires and nanotubes have attract intensive interest in various applications including gas sensors and thermoelectrics, due to their unique size-dependent electrical, thermal transport and mechanical properties. Miniature and portable gas sensors are of great importance in detecting gaseous molecules for environmental pollution analysis, homeland security, industrial emission control and outer space exploration. Thermoelectric energy converters, which generate electricity by harvesting waste thermal energy, can improve the efficiency of environmentally-friendly and renewable energy generation. The overall objective of this work is to engineer one-dimensional nanostructures using various techniques such as electrospinning and electrochemical routes for thermoelectric and gas sensor applications.

Electrospinning and galvanic displacement reaction were combining to synthesize ultra-long metal chalcogenide nanofibers with controlled dimensions, morphologies, and compositions. The structure, electrical and thermoelectric properties were systematically examined to understand relationships between nanofiber structures and their resulting thermoelectric performance.

In addition to thermoelectrics, high performance nano gas sensor were realized by either surface functionalizing CNTs with various Te morphologies or contacting the CNT with various electrodes for different types of electrical contacts (i.e. ohmic and Schottky contacts). An understanding of the underlying fundamental sensing mechanism was investigated to fabricate a high-performance gas sensor array.