Work function reduction of graphitic nanofibers by potassium intercalation
Date of this VersionAugust 2005
APPLIED PHYSICS LETTERS 87, 061501 !2005"
The authors wish to tahnk Eve S. Steigerwalt for generation of TEM images. They also acknowledge financial support of this work through the National Science Foundation's Nanoscale Interdisciplinary Research Team program.
This document has been peer-reviewed.
Materials with low work functions hold great potential for improving the performance of thermionic energy converters and other thermionic emission devices. Thermionic electron energy distributions !TEEDs" of graphitic carbon nanofibers !GCNFs" with and without intercalated potassium are used to characterize performance under realistic operating conditions. TEEDs of intercalated GCNFs at temperatures of 600 and 700 °C reveal an effective work function of 2.2 eV, a reduction of 2.5 eV from the work function of the GCNF without intercalate. In addition, consistent with other published work, a narrowing of the electron energy spectrum’s width occurs with intercalation. This narrower energy distribution may indicate emission from hybridized carbon–potassium states.