Transient Thermal Response of Hotspots in Graphene–Silver Nanowire Hybrid Transparent Conducting Electrodes

Graphene-nanowire hybrid films have recently shown excellent performance as transparent conducting electrodes. However, due to their fundamental nonhomogeneity (grain boundaries, nanowire-nanowire junctions), self-heating induces hotspots along the co-percolating electrical conduction pathways. Alth...

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Bibliographic Details
Published in:IEEE transactions on nanotechnology 2018-03, Vol.17 (2), p.276-284
Main Authors: Sadeque, Sajia, Gong, Yu, Maize, Kerry, Ziabari, Amir K., Mohammed, Amr M. S., Shakouri, Ali, Janes, David B.
Format: Article
Language:English
Subjects:
high-resistance grain boundaries
Hybrid graphene–silver nanowire
Immune system
Junctions
Light emitting diodes
percolation transport
Resistance
Resistance heating
self-heating
thermoreflectance imaging
Transient analysis
transparent conducting electrodes
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Summary:Graphene-nanowire hybrid films have recently shown excellent performance as transparent conducting electrodes. However, due to their fundamental nonhomogeneity (grain boundaries, nanowire-nanowire junctions), self-heating induces hotspots along the co-percolating electrical conduction pathways. Although the steady-state characteristics of the hotspot temperature and location have been reported, the temporal response of the hotspots has not been studied in detail. In this paper, we use transient thermoreflectance imaging with high temporal resolution to quantify the transient characteristics of the hotspots. At local hotspots as well as nearby intermediate temperature regions, the temperature response in both heating and cooling phases exhibits two distinct time constants. We quantitatively determine the thermal time constants and associated amplitudes and show dependence of these parameters on distance from the contact. Based on solutions to heat diffusion equations, the short-time constant is attributed to the local self-heating within the hotspot region, and the long-time constant to diffusion of heat through the channel region. The knowledge of time evolution of hotspots and hence a more detailed understanding of the electrothermal conduction process through co-percolating networks could enable more reliable, advanced transparent conductors as well as one-dimensional/two-dimensional hybrid materials for other applications.
ISSN:1536-125X
1941-0085
DOI:10.1109/TNANO.2018.2794782