Optimizing Single‐Walled Carbon Nanotube Films for Applications in Electroluminescent Devices

Wang, Yu; Di, Chong‐an; Liu, Yunqi; Kajiura, Hisashi; Ye, Shanghui; Cao, Liqin; Wei, Dacheng; Zhang, Hongliang; Li, Yongming; Noda, Kazuhiro

doi:10.1002/adma.200801088

Cited by 94 publications

(79 citation statements)

References 71 publications

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“…Thus, it is clear that nitric acid is a very effective p-type dopant for transparent conducting SWNT films, in agreement with reports on thick, opaque SWNT ''bucky-papers''. [18] Figure 1e shows that several small peaks due to the polymer matrix remain following treatment with 4 M HNO 3 . Gravimetric and infrared studies indicate that the remaining polymer ($2-4 wt% of the initial polymer) is removed by a subsequent treatment with concentrated (16 M) nitric acid.…”

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Ultrasmooth, Large‐Area, High‐Uniformity, Conductive Transparent Single‐Walled‐Carbon‐Nanotube Films for Photovoltaics Produced by Ultrasonic Spraying

et al. 2009

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Transparent conducting (TC) films of single-walled carbon nanotubes (SWNTs) have the potential to replace conventional TC oxides in a wide variety of optoelectronic devices. [1][2][3][4][5] TC-SWNT films are particularly attractive for photovoltaics (PV) due to their high transparency over much of the solar spectrum, excellent electrical conductivity, and the potential for inexpensive roll-to-roll processing. SWNT films have been used, by us and others, in cadmium telluride, [6] copper indium gallium diselenide, [7] and organic PV (OPV) devices. [8][9][10] In several reports, SWNTelectrodes for OPV have been prepared by filtering a sodium dodecyl sulfate (SDS)-stabilized dispersion of SWNTs to form a thin film. [9,10] The film can be released by dissolution of the filter, and then transferred to a transparent substrate.[11] This so-called ''transfer method'' produces highly transparent films with excellent conductivity, but the films possess irregular morphologies and significant roughness, which can lead to short-circuits and overall poor reproducibility during device fabrication.[12] Moreover, the process is not scalable. TC-SWNT films have also been produced for optical and electrical studies by air-brush spraying using surfactant-stabilized SWNT inks. Such films are inhomogeneous because SWNTs sprayed from surfactant solutions agglomerate on heated substrates. To move TC-SWNT electrodes beyond the proof-of-concept stage for PV and other optoelectronic applications, methods are required for producing large-area, transparent, conducting SWNT films that are smooth and homogeneous over large areas.Here, we report methods to prepare SWNT films with high transparency, electrical conductivity, and uniformity, with exceptionally low surface roughness, on arbitrarily large (6 inch Â 6 inch) substrates by ultrasonic spraying. A side-by-side comparison of OPV devices fabricated on SWNT and indiumdoped tin oxide (ITO) electrodes showed very good performance with energy-conversion efficiencies of $3.1 and 3.6%, respectively, under AM 1.5 illumination. Several factors are critical to the success of the approach. First, we prepared aqueous SWNT dispersions using a high-molecular-weight (MW $90 000) polymeric derivative of cellulose (sodium carboxymethyl cellulose (CMC)). CMC has been previously reported as an excellent agent for dispersing SWNTs in water, [13] and transparent films have been drop-cast, [14] but this is the first report of CMC-based dispersions for spraying SWNT films. A second advance is the use of ultrasonic spraying, which, when combined with the CMC-based dispersions, permits precise amounts of SWNTs to be reproducibly and uniformly dispensed over arbitrarily large areas. In fact, by measuring the weight and optical properties of films as a function of the number of deposited layers, the SWNT absorption coefficient could be accurately determined. Finally, we used SWNTs produced by laser vaporization (LV), which have lower defect densities [15,16] than tubes produced by chemical vapor deposition (CVD). Th...

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confidence: 96%

Ultrasmooth, Large‐Area, High‐Uniformity, Conductive Transparent Single‐Walled‐Carbon‐Nanotube Films for Photovoltaics Produced by Ultrasonic Spraying

et al. 2009

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“…In addition to its flexibility, CNT films also show high transparency in a large range of solar spectrum as compared to ITO which has excellent transparency in the visible range. In recent years, transparent CNT thin films have been studied and tested in a variety of optoelectronic devices [6][7][8][9][10].…”

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Highly conductive and transparent carbon nanotube composite thin films deposited on polyethylene terephthalate solution dipping

et al. 2010

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“…In the case of chemical vapor deposition (CVD) graphene, however, serious problems such as the defects in the crystal, wrinkles and a high sheet resistance were observed. [10][11][12][13][14] For these reasons, many researchers have investigated various doping methods including chemical, [16][17][18][19][20] plasma, [21][22][23] and photochemical methods for large area CVD graphene. 24 However, these approaches showed severe damage to the carbon network in the graphene, and resulted in the rapid degradation on device performances.…”

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Chlorine Radical Doping of a Few Layer Graphene with Low Damage

Kim

Pham

Yeom

2015

ECS J. Solid State Sci. Technol.

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We present a graphene plasma doping method using chlorine radicals generated in an inductively coupled plasma (ICP) with a double mesh grid system. Raman spectroscopy and sheet resistance measurement showed that this doping method is non-destructive and controllable approach for the p-type graphene layer doping method. And, by using a chlorine trap-doping method, the sheet resistance could be decreased to 76% at an optimized condition for the tri-layer graphene.

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Optimizing Single‐Walled Carbon Nanotube Films for Applications in Electroluminescent Devices

Cited by 94 publications

References 71 publications

Ultrasmooth, Large‐Area, High‐Uniformity, Conductive Transparent Single‐Walled‐Carbon‐Nanotube Films for Photovoltaics Produced by Ultrasonic Spraying

Ultrasmooth, Large‐Area, High‐Uniformity, Conductive Transparent Single‐Walled‐Carbon‐Nanotube Films for Photovoltaics Produced by Ultrasonic Spraying

Highly conductive and transparent carbon nanotube composite thin films deposited on polyethylene terephthalate solution dipping

Chlorine Radical Doping of a Few Layer Graphene with Low Damage

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