M. Arjmand a, L. Laurentius b , U. Sundararaj a Nitrogen-Doped Carbon Nanotube / Polymer Nanocomposites: Versatile Materials for Charge Storage M. Arjmand a, L. Laurentius b , U. Sundararaj a a Department of Chemical and Petroleum Engineering, University of Calgary b Department of Chemistry, National Institute for Nanotechnology, University of Alberta CSChE 2015

CHRONOLOGICAL DEVELOPMENT OF CAPACITORS Conventional Capacitors like Ceramic Capacitors High-k Ceramic Powder / Polymer Capacitors Conductive Filler / Polymer Capacitors (CPCs)

WHAT MAKES A CPC UNIQUE FOR CHARGE STORAGE? Nano-Capacitor: Conductive Filler as Nanoelectrode and Polymer Matrix as Nanodielectric

DIELECTRIC RESPONSE TO APPLIED ELECTRIC FIELD Interfacial Log (ε′) X-Band (8.2-12.4 GHz) 3 8 12 15 Log (Frequency (Hz))

Polarization Mechanisms Over the X-Band (8.2-12.4 GHz) Interfacial × Dipolar (PVDF Matrix) × CNT Polarization Yes Electronic Polarization Yes

Unrolled Undoped and Nitrogen Doped Carbon Nanotube Under Electric Field

Chemical Vapor Deposition (CVD) Setup

X-ray Photoelectron Spectroscopy

Transmission Electron Microscopy Nitrogen-Doped CNTs Undoped CNTs

Raman Spectroscopy Sample # ID/IG IGʹ/IG N-doped Nanocomposites 0.82 0.21 Undoped Nanocomposites 0.66 0.94

Length and Diameter

Percolation Curve

Dielectric Permittivity and Loss

Conceptualization of Imaginary Permittivity + + +

Real Permittivity The electric dipole has a magnitude equals the strength of each charge times the separation distance between charges. Real permittivity represents the magnitude and quantity of dipoles.

Dissipation Factor Sample # Real Permittivity Dielectric Loss N-doped Nanocomposites 9 1.96 Undoped Nanocomposites 6.21

Conclusions Nitrogen doping deteriorated the crystallinity and metallicity of carbon nanotubes. The positive impact of nitrogen doping on lowering the dielectric loss overshadowed it negative impact on reducing dielectric permittivity. Nitrogen doping can be used as an efficient technique to tune the dielectric properties of carbon nanotube/polymer nanocomposites.

Acknowledgements Natural Sciences and Engineering Research Council (NSERC) of Canada Dr. Kambiz Chizari and Mr. Abdalla for their assistance with carbon nanotube synthesis and nanocomposite preparation.

Thanks For Your Attention ! marjmand@ucalgary.ca u.sundararaj@ucalgary.ca

Back-Up Slides

Parameters Affecting Electrical Properties of N-CNT/Polymer Nanocomposite Synthesis Yield (TGA) Length and Diameter (TEM) Crystallinity (Raman Spectroscopy) Metallicity (Raman Spectroscopy and STS) Nitrogen Content and Bonding Type (XPS)

Light Microscopy

Relative Transparency

N-CNT Growth Mechanism (Cont’d) Reyes-Reyes M, Grobert N, Kamalakaran R, Seeger T, Golberg D, Ruhle M, et al.. Chem Phys Lett 2004;396(1-3):167-73.

N-CNT Growth Mechanism Bamboo-Shaped Fe Catalyst Open-Channel Co Catalysts van Dommele S, Romero-Izquirdo A, Brydson R, de Jong KP, Bitter JH. Carbon 2008;46(1):138-48. Hofmann S, Sharma R, Ducati C, Du G, Mattevi C, Cepek C, et al. Nano Lett 2007;7(3):602-8.

What Makes CPC Different For Use As Charge Storage Material? The electric dipole has a magnitude equals to the strength of each charge times the separation between charges. Interfacial Polarization + + + + - + + + + + Electronic Polarization

Embedded Capacitor In a typical microelectronic product, around 80% of the electronic components are passive components, such as capacitors, which take up more than 40% of the printed circuit board (PCB) surface area.1 2 1 J. X. Lu, K. S. Moon, J. W. Xu, and C. P. Wong, J. Mater. Chem. 16 (16), 1543 (2006). 2 www.murata.com

What Makes Doping Important for Electronic Properties? Isolator-Metal. Available from: http://commons.wikimedia.org/wiki/File:Isolator-metal.svg http://www.physics.udel.edu/~watson/scen103/98w/clas0128b.html

Different Types of Nitrogen Bonding in Graphitic Structures Wei DC, Liu YQ, Wang Y, Zhang HL, Huang LP, Yu G. Nano Lett 2009;9(5):1752-8.

Nitrogen-doped (N-CNT) Synthesis Procedure Incipient wetness impregnation of catalyst precursors (Metal Nitrate and Sulfate Components) onto Alumina Support Drying (25ºC) - Calcination with air at 350ºC – Reduction with Hydrogen at 400ºC Synthesis at 750ºC for 2h – Precursor Gases (Ethane and Ammonia) - Carrier Gas (Hydrogen)

X-ray Photoelectron Spectroscopy

Doping of Carbon Nanotubes: Why Nitrogen and Boron?

TGA Analysis Sample # Inflection Point (ºC) N-doped Nanocomposites 517 Undoped Nanocomposites 650

Challenges in Manipulating CPCs as Charge Storage Materials High real permittivity is achievable close to or above percolation threshold.1 The insulator–conductor transition, which occurs at percolation threshold, precludes CPCs being used above the percolation threshold. There is a typically narrow insulator-conductor transition window to regulate dielectric properties. 1Dang ZM, Yao SH, Yuan JK, and Bai JB. J Phys Chem C 2010; 114: 13204-9.