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Title: Thermionic cooling with functionalized carbon nanotube thin films

A large thermionic cooling effect is reported. Temperature reduction as much as 81 °C has been observed on a functionalized carbon nanotubes (CNTs) cathode surface. This cathode utilizes a thin coating of low work function barium strontium oxide emissive materials on top of the CNTs to lower the surface work function. This, combined with the field effect induced by the CNTs, results in an even lower effective work function, and thus strong thermionic emission. Strong thermionic emission is the underlying reason for the large cooling effect observed, and the largest emission current in this study is around 160 mA on a 0.0727 cm{sup 2} emitting surface at around 995 °C. Multiple samples were used in studying thermionic mission at cathode temperature ranging between 750 °C and 1100 °C, and in establishing correlation between the cooling effect and the emission current. Details of the cooling effect measurement are provided, and the measurement results show a clear linear dependence of temperature drop on thermionic emission current. The possible implication of this linear dependence is also discussed.
Authors:
 [1] ;  [2]
  1. Department of Physics and Astronomy, Ball State University, Muncie, Indiana 47306 (United States)
  2. Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)
Publication Date:
OSTI Identifier:
22395765
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; BARIUM COMPOUNDS; CARBON NANOTUBES; CATHODES; COOLING; CORRELATIONS; STRONTIUM OXIDES; SURFACES; THERMIONIC EMISSION; THIN FILMS; WORK FUNCTIONS