Aerosol CVD synthesis and applications of single-walled carbon nanotube thin films using spark-discharged produced catalyst

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School of Science | Doctoral thesis (article-based) | Defence date: 2020-04-17
Degree programme
78 + app. 51
Aalto University publication series DOCTORAL DISSERTATIONS, 44/2020
Structural controlled synthesis of single-walled carbon nanotubes (SWCNTs) have attracted a great deal of attention due to their widespread potential applications in electronics and photonics. Floating catalyst chemical vapor deposition (FC-CVD) being a dry and continuous method, is a highly promising technique for the scalable synthesis of SWCNTs. However, due to in-situ catalyst formation in all the conventional FC-CVD approaches, it is hard to get full control of number concentration, composition and size of nanoparticles. Hence, it hinders to investigate the effects of catalyst composition on morphology, yield and structure of SWCNTs. In this thesis, firstly we designed a novel rod-to-tube type spark discharge generator (R-T SDG) to produce ex-situ catalyst nanoparticles for the FC-CVD growth of SWCNTs. We utilized highly time-stable and uniform number size distributions of monometallic (Fe, Ni, Co) and bimetallic (Co-Fe, Co-Ni) catalyst particles for the synthesis of SWCNTs using ethylene as carbon source and 1050 deg C temperature. Optical characterizations revealed that as-grown SWCNTs have high-quality and their mean diameter is around 1 nm. The highest SWCNTs yield was obtained with Fe as a catalyst. From electron diffraction analysis, we observed that Co-Ni can produce comparatively narrower chirality and diameter distribution of SWCNTs. Secondly, we introduced sulfur in the FC-CVD reactor as a growth promoter for the fabrication of SWCNTs based transparent conducting films (TCFs). We systematically investigated the roles of sulfur on yield, morphology, and structure of SWCNTs. It was found that the yield of SWCNTs is largely dependent on amount of sulfur introduced into the FC-CVD reactor and catalyst composition. More importantly, the addition of an optimized amount of sulfur has enhanced approximately three times, the opto-electronic performance of SWCNT-TCFs, by increasing diameter and bundle length along with improving the quality of SWCNTs. The mean diameter of SWCNTs increased from 1 nm to 1.2 nm while the ratio of metallic nanotubes slightly increased from 39 % to 41 % with sulfur addition. Surprisingly, chirality determination of as-grown SWCNTs indicated that sulfur promotor has little influence on modulating the chirality of SWCNTs. Finally, we demonstrated that FC-CVD is a unique and versatile technique for the simultaneous growth of substrate-free 0D-fullerene, 1D-CNT and 2D-graphene. The formation of 0D-1D-2D carbon nanostructures were directly evidenced by lattice-resolved (scanning) transmission electron microscopy (STEM). We showed that the relative number density of graphene-nanoflakes can be tuned by optimizing the synthesis conditions. In addition, the as-synthesized hybrid films can be directly deposited on any surface at ambient temperature with an arbitrary thickness which offers a new route towards ultra-fast manufacturing and dry deposition of the hybrid structures.
The public defense will be organized on 17th April 2020 at 12:00 via remote technology. Link: Zoom Quick Guide:
Supervising professor
Kauppinen, Esko I., Prof., Aalto University, Department of Applied Physics, Finland
Thesis advisor
Zhang, Qiang, Dr., Aalto University, Department of Applied Physics, Finland
floating-catalyst CVD, single-walled carbon nanotubes, pre-made catalyst, ethylene, transparent conducting film, low dimensional carbon nanostructures
Other note
  • [Publication 1]: Ahmad, Saeed; Laiho, Patrik; Zhang, Qiang; Jiang, Hua; Hussain, Aqeel; Liao, Yongping; Ding, Er-Xiong; Wei, Nan; Kauppinen, Esko I. Gas phase synthesis of metallic and bimetallic catalyst nanoparticles by rod-to-tube type spark discharge generator. Journal of aerosol science, 2018, volume 123, pages 208-218.
    DOI: 10.1016/j.jaerosci.2018.05.011 View at publisher
  • [Publication 2]: Ahmad, Saeed; Liao, Yongping; Hussain, Aqeel; Zhang, Qiang; Ding, Er-Xiong; Jiang, Hua; Kauppinen, Esko I. Systematic investigation of the catalyst composition effects on single-walled carbon nanotubes synthesis in floating-catalyst CVD. Carbon, 2019, volume 149, pages 318-327.
    Full text in Acris/Aaltodoc:
    DOI: 10.1016/j.carbon.2019.04.026 View at publisher
  • [Publication 3]: Ahmad, Saeed; Ding, Er-Xiong; Zhang, Qiang; Jiang, Hua; Sainio, Jani; Tavakkoli, Mohammad; Hussain, Aqeel; Liao, Yongping; Kauppinen, Esko I. Roles of sulfur in floating-catalyst CVD growth of single-walled carbon nanotubes for transparent conductive film applications. Elsevier. Chemical engineering journal, 2019, volume 378 (122010), pages 1-8.
    Full text in Acris/Aaltodoc:
    DOI: 10.1016/j.cej.2019.122010 View at publisher
  • [Publication 4]: Ahmad, Saeed; Mustonen, Kimmo; McLean, Ben; Jiang, Hua; Zhang, Qiang; Hussain, Aqeel; Taher Khan, Abu; Ding, Er-Xiong; Liao, Yongping; Nasibulin, Albert G.; Kotakoski, Jani; Page, Alister J.; Kauppinen, Esko I. Simultaneous growth of free-standing 0D-1D-2D carbon nanostructures through one-step gas-phase synthesis techniques. Submitted to Nature December-2019 (12 pages).