Catalyst and chirality dependent growth of carbon nanotubes determined through nano-test tube chemistry.


Single-walled carbon nanotubes (SWCNTs) have attracted much interest for their unique nanostructural and electronic properties, which have a wide range of potential applications. The key barrier that prevents SWCNTs fulfi lling their potential in electronic applications is the understanding of the growth mechanism and, as a consequence, the inability to control the tube size, chirality, and hierarchy in the structure on a bulk scale. The synthesis of SWCNTs in general requires metal nanocompounds to catalyze the growth. Notably successful catalysts include Fe, Ni, and Co. Noble metals (Au, Ag, Pt, and Pd) have recently been reported to catalyze the growth of carbon nanotubes as well. [ 1 , 2 ] While recent improvements in yield, purity, and selectivity were obtained by using a variety of bulk synthesis techniques, individual chemical processes have rarely been observed. Nano-test tube chemistry uses the hollow space inside SWCNTs as a controlled local environment to perform syntheses. The hollow space inside SWCNTs can be utilized for the encapsulation of atoms and molecules in a highly controlled manner. A large variation of fullerene materials and organic molecules have thus far been encapsulated inside carbon nanotubes. [ 3–12 ] Such fi lled nanotubes allow chemical reactions to be confi ned at the nanometer-scale such that novel chemistry processes can occur and the individual chemical events can be observed at the molecular level. Preliminary research on nano-test tube chemistry includes the transformation of SWCNTs encapsulating molecules into double-walled carbon nanotubes (DWCNTs). [ 11–15 ] It has been reported that the encapsulated reactions can also lead to functionalization of the original carbon nanotubes. [ 16 , 17 ] These papers highlight the potential merits of encapsulation and

DOI: 10.1002/adma.201001211

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@article{Shiozawa2010CatalystAC, title={Catalyst and chirality dependent growth of carbon nanotubes determined through nano-test tube chemistry.}, author={Hidetsugu Shiozawa and Christian Kramberger and Rudolf Arthur Pfeiffer and Hans Kuzmany and Thomas Pichler and Zheng Liu and Kazu Suenaga and Hiromichi Kataura and S. R. P. Silva}, journal={Advanced materials}, year={2010}, volume={22 33}, pages={3685-9} }