Temperature-dependent electrical properties of graphene nanoplatelets film dropped on flexible substrates
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Huanga) Department of Electronic Science and Applied Physics, Hefei University of Technology, Hefei 230009, People’s Republic of China; and Institute of Intelligence Machines, Chinese Academy of Sciences, Hefei 230031, People’s Republic of China
Weihua Wang, Ruiqi Li, Ping Liu, Caixia Liu, and Yugang Zhang Department of Electronic Science and Applied Physics, Hefei University of Technology, Hefei 230009, People’s Republic of China (Received 19 February 2014; accepted 30 April 2014)
The fabrication of a temperature sensor based on graphene nanoplatelets (GNPs) is reported. A preheat process was carried out and the micrographs of both original and preheat-treated GNPs are observed and compared. Nonlinear temperature variation of resistance is observed and humidity interference is found to be negligible. Region of 10–60 °C (the linear region) is selected as the sensor range and further studied. High sensitivity of GNPs can be seen and the temperature coefficient of resistance (TCR) of 0.0371 is calculated, higher than that of multiwall carbon nanotubes (MWCNTs) and many other materials reported in references. Great repeatability and small hysteresis are obtained. The time constant of the GNPs film is about 5 s, much shorter than that of MWCNTs film. The result suggests that GNPs have potential applications for use in highly sensitive and fast-response temperature sensors.
I. INTRODUCTION
Relevant implications that temperature sensor has in everyday life, including important applications in fields such as biomedicine, food industry, and aerospace industry, have prompted an intensive research concerning new sensing materials.1,2 The main requirements of a good temperature sensor are high sensitivity, fast response, low cost, and high reliability. Up to now, temperature sensors are mostly based on metal3,4 and metal oxide semiconductors.5 Moreover, the birth of artificial skins6–8 and wearable electronic devices9,10 has boosted many efforts toward the miniaturization of sensors as they would lead to soft and flexible materials. In this direction, graphene has received significant attention because of its potential as highly flexible electrically conductive electronics for various applications.11 While two-dimensional (2-D) graphene nanoplatelets (GNPs) have inherited the excellent sensing function of graphene, the low cost and ease of production make it more commonly used. GNPs have drawn a lot of interest and possess many advantages compared with graphite due to their high mechanical properties (about 1 TPa for either single-layer or multilayer graphene12), excellent electrical conductivity (about 1.0 106 Xcm resistivity for pure graphene but more than two orders a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2014.109 1288
J. Mater. Res., Vol. 29, No. 11, Jun 14, 2014
http://journals.cambridge.org
Downloaded: 03 Jan 2015
of magnitude higher for graphite13), thermal conductivity (about 5000 W/mK,14–17 much higher than that for graphite with thermal conductivity of 5–20 W/mK), and
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