Thermoelectric Properties of Nanowires with a Graphitic Shell

• Published in: ChemSusChem 2015-07, Vol.8 (14), p.2372-2377
• Main Authors: Lee, Jong Woon, Lee, Eun Kyung, Kim, Byung Sung, Lee, Jae Hyun, Kim, Hee Goo, Jang, Hyeon Sik, Hwang, Sung Woo, Choi, Byoung Lyong, Whang, Dongmok
• Format: Article
• Language: English
• Subjects: conducting materials; core-shell structure; Electric Conductivity; Electric Power Supplies; Graphite - chemistry; graphitic layer; Hot Temperature; nanostructures; Nanowires - chemistry; Shells; Silicon - chemistry; Silicon Dioxide - chemistry; thermal conductivity
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201403492

A thermoelectric device that can generate electricity from waste heat can play an important role in a global energy solution. However, the strongly correlated thermoelectric properties have remained a major hurdle for the highly efficient conversion of thermoelectric energy. Herein, the electrical and thermal properties of Si and SiO2 nanowires with few‐layer graphitic shells are demonstrated; these structures exhibit enhanced electrical properties but no increase in thermal conductivity. The main path of the phonons through the structures is the core nanowire, which has a large cross‐sectional area relative to that of the graphitic shell layer. However, the electrical conductivities of the nanowires with shell structures are high because of the good electrical conductivity of the graphitic shell, despite its small cross‐sectional area. Cool under fire: The electrical and thermal properties of Si and SiO2 nanowires with a few‐layer graphitic shell are explored; these structures exhibit enhanced electrical properties but no increase in thermal conductivity. Phonons are transported through the core nanowire, which has a large cross‐sectional area relative to that of the graphitic shell, and the main current path is the graphitic shell owing to its good electrical conductivity.