Browsing by Author "Sun, Dong Ming"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Growth of semiconducting single-wall carbon nanotubes with a narrow band-gap distribution
    (2016-03-30) Zhang, Feng; Hou, Peng Xiang; Liu, Chang; Wang, Bing Wei; Jiang, Hua; Chen, Mao Lin; Sun, Dong Ming; Li, Jin Cheng; Cong, Hong Tao; Kauppinen, Esko I.; Cheng, Hui Ming; Department of Applied Physics; NanoMaterials; Chinese Academy of Sciences; King Abdulaziz University
    The growth of high-quality semiconducting single-wall carbon nanotubes with a narrow band-gap distribution is crucial for the fabrication of high-performance electronic devices. However, the single-wall carbon nanotubes grown from traditional metal catalysts usually have diversified structures and properties. Here we design and prepare an acorn-like, partially carbon-coated cobalt nanoparticle catalyst with a uniform size and structure by the thermal reduction of a [Co(CN)6 ]3- precursor adsorbed on a self-assembled block copolymer nanodomain. The inner cobalt nanoparticle functions as active catalytic phase for carbon nanotube growth, whereas the outer carbon layer prevents the aggregation of cobalt nanoparticles and ensures a perpendicular growth mode. The grown single-wall carbon nanotubes have a very narrow diameter distribution centred at 1.7 nm and a high semiconducting content of > 95%. These semiconducting single-wall carbon nanotubes have a very small band-gap difference of ~ .08 eV and show excellent thin-film transistor performance.
  • Thumbnail Image
    Item
    Key factors for ultra-high on/off ratio thin-film transistors using as-grown carbon nanotube networks
    (Royal Society of Chemistry, 2022-06-01) Sun, Yun; Li, Pengpeng; Kauppinen, Esko I.; Sun, Dong Ming; Ohno, Yutaka; Department of Applied Physics; NanoMaterials; CAS - Institute of Metal Research; Nagoya University
    Approximately 30% of as-grown carbon nanotube (CNT) networks are metallic, usually leading to a trade-off between carrier mobility and on/off ratio in CNT thin-film transistors (TFTs). Figuring out the key factors of ultra-high on/off ratio in CNT TFTs should be considerably essential for the development of large-scale electronic devices in the future. Here ultra-high on/off ratios of 107-108 are realized for CNT TFTs with mobility of ∼500 cm2 V−1 s−1. We propose that one of the key factors to achieve the high on/off ratio is a clean CNT thin film without charge traps and doping due to residual dispersant used in conventional solution processes. Moreover, on/off ratio degradation under operation voltage is significantly suppressed by decreasing the diameter of CNTs.
  • Thumbnail Image
    Item
    Ultrahigh-performance transparent conductive films of carbon-welded isolated single-wall carbon nanotubes
    (2018-05-04) Jiang, Song; Hou, Peng Xiang; Chen, Mao Lin; Wang, Bing Wei; Sun, Dong Ming; Tang, Dai Ming; Jin, Qun; Guo, Qing Xun; Zhang, Ding Dong; Du, Jin Hong; Tai, Kai Ping; Tan, Jun; Kauppinen, Esko I.; Liu, Chang; Cheng, Hui Ming; Department of Applied Physics; NanoMaterials; Chinese Academy of Sciences; Changchun Institute of Applied Chemistry
    Single-wall carbon nanotubes (SWCNTs) are ideal for fabricating transparent conductive films because of their small diameter, good optical and electrical properties, and excellent flexibility. However, a high intertube Schottky junction resistance, together with the existence of aggregated bundles of SWCNTs, leads to a degraded optoelectronic performance of the films. We report a network of isolated SWCNTs prepared by an injection floating catalyst chemical vapor deposition method, in which crossed SWCNTs are welded together by graphitic carbon. Pristine SWCNT films show a record low sheet resistance of 41 ohm -1 at 90% transmittance for 550-nm light. After HNO3 treatment, the sheet resistance further decreases to 25 ohm -1. Organic light-emitting diodes using this SWCNT film as anodes demonstrate a low turn-on voltage of 2.5 V, a high current efficiency of 75 cd A-1, and excellent flexibility. Investigation of isolated SWCNT-based field-effect transistors shows that the carbon-welded joints convert the Schottky contacts between metallic and semiconducting SWCNTs into near-ohmic ones, which significantly improves the conductivity of the transparent SWCNT network. Ourwork provides a new avenue of assembling individual SWCNTs into macroscopic thin films, which demonstrate great potential for use as transparent electrodes in various flexible electronics.