Control of Nanoscale Thermal Transport for Thermoelectric Energy Conversion and Thermal Rectification

Materials at the nanoscale show properties uniquely different from the bulk scale which when controlled can be utilized for variety of thermal management applications. Different applications require reduction, increase or directional control of thermal conductivity. This thesis focuses on investigating thermal transport in two such application areas, viz., 1) thermoelectric energy conversion and 2) thermal rectification. Using molecular dynamics simulations, several methods for reducing of thermal conductivity in polyaniline and polyacetylene are investigated. The reduction in thermal conductivity leads to improvement in thermoelectric figure of merit. Thermal diodes allow heat transfer in one direction and prevents in the opposite direction. These materials have potential application in phononics, i.e., for performing logic calculations with phonons. Rectification obtained with existing material systems is either too small or too difficult to implement. In this thesis, a more useful scheme is presented that provides higher rectification using a single wall carbon nanotube (SWCNT) that is covalently functionalized near one end with polyacetylene (PA). Although several thermal diodes are discussed in literature, more complex phononic devices like thermal logic gates and thermal transistors have been sparingly investigated. This thesis presents a first design of a thermal AND gate using asymmetric graphene nanoribbon (GNR) and characterizes its performance.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Engineering Mechanics

Department dc:contributor.department

Engineering Science and Mechanics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2013

Author dc:creator

• Pal, Souvik

Chairs dc:contributor.committeechair

• Puri, Ishwar K.
• Hajj, Muhammad R.

Committee members dc:contributor.committeemember

• Stremler, Mark A.
• De Vita, Raffaella
• Al-Haik, Marwan
• Patil, Mayuresh J.

• Nanoscale heat transfer
• molecular dynamics
• thermoelectric energy
• thermal rectification
• phononics

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:1783

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/52935