Counter-ion Dependent, Longitudinal Unzipping of Multi-Walled Carbon Nanotubes to Highly Conductive and Transparent Graphene Nanoribbons

• Published in: Scientific reports 2014-03, Vol.4 (1), p.4363, Article 4363
• Main Authors: Shinde, Dhanraj B., Majumder, Mainak, Pillai, Vijayamohanan K.
• Format: Article
• Language: English
• Subjects: 639/301/1005/1007; 639/301/357/918/1055; 639/925; 639/925/918/1052; Electric Conductivity; Graphite; Humanities and Social Sciences; Hydroxides - chemistry; Materials Testing; multidisciplinary; Nanotubes, Carbon - chemistry; Nitrates - chemistry; Potassium Compounds - chemistry; Science; Sulfates - chemistry; Sulfuric Acids - chemistry
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep04363

Here we report for the first time, a simple hydrothermal approach for the bulk production of highly conductive and transparent graphene nanoribbons (GNRs) using several counter ions from K 2 SO 4 , KNO 3 , KOH and H 2 SO 4 in aqueous media, where, selective intercalation followed by exfoliation gives highly conducting GNRs with over 80% yield. In these experiments, sulfate and nitrate ions act as a co-intercalant along with potassium ions resulting into exfoliation of multi-walled carbon nanotubes (MWCNTs) in an effective manner. The striking similarity of experimental results in KOH and H 2 SO 4 that demonstrates partially damaged MWCNTs, implies that no individual K + , SO 4 2− ion plays a key role in unwrapping of MWCNTs, rather this process is largely effective in the presence of both cations and anions working in a cooperative manner. The GNRs can be used for preparing conductive 16 kΩsq −1 , transparent (82%) and flexible thin films using low cost fabrication method.