Achieving High Mid‐IR Bolometric Responsivity for Anisotropic Composite Materials from Carbon Nanotubes and Polymers

Abstract

An anisotropic carbon nanotube (CNT)-polymer composite for bolometric applications in the mid-IR spectral range (2.5-20 μ m) is studied. Composite alignment in conjunction with non-uniform distribution of CNTs in the polymer matrix allows for a signifi cant enhancement of the temperature coefficient of resistance (0.82% K − 1 ) with respect to uniform composite (0.24% K − 1 ). As a result a responsivity of ≈ 500 V W − 1 is reached, which is the highest for CNT-based bolometers reported to date. Such remarkable optical and thermal characteristics are explained in terms of fl uctuation tunneling theory taking into account the composite anisotropy and the gradient of the CNT concentration. Flatness of the photoresponse in the broad spectral mid-IR range and enhanced responsivity provide a great potential for the use of such novel composite for applications in IR spectroscopy and thermal imaging.

Uncooled Carbon Nanotube Photodetectors

“…Reproduced with permission. [85] Copyright 2012, Wiley. b)The on-off photoresponse of a bolometer based on one layer of super aligned MWCNT film under an IR radiation of 10 mW/mm 2 with the polarization direction of incident beam parallel to the alignment direction of CNT film in vacuum at room temperature.…”

“…As far as the first aspect is concerned, many methods have been explored such as the variation of the CNT film thickness, [54] sorting the CNTs by electronic type, [33] investigating the optimal diameter distribution of CNTs, [94] and engineering the activation energy for charge transport at inter-tube junctions by embedding CNTs into a polymer matrix. [84][85][86][95][96][97] As for the second aspect, the focal point is how to suspend the device efficiently through various techniques. [82,88] During the last decade, CNT-based bolometric detectors have made substantial progress and the performances of these detectors is continuously being improved.…”

Midinfrared Surface Plasmons in Carbon Nanotube Plasmonic Metasurface

“…Starting from the pioneering work of Itkis et al [39] many studies were performed to increase the efficiency of SWCNT-based bolometers. Embedding SWCNTs to the polymer [40][41][42] leads to the growth of the composite TCR up to 10% K −1 which is greater than the TCR of commercially used vanadium oxide [43] and silicon and also improves the mechanical stability of the device. The drawback of the composite bolometers is the longer response time determined by a larger amount of material which has to be heated.…”

All-carbon nanotube diode and solar cell statistically formed from macroscopic network

“…On the other hand, Nano Res. macroscopic SWNT networks (SWNT films), which are free from the "nanoscale problem", have been broadly utilized for various optoelectronic applications such as transparent conductive coatings [2], photovoltaics [3][4][5], and optical sensing [6][7][8][9][10][11][12].…”