The pyrolysis process of organic molecules accommodated inside porous nanochannels of AlP0₄ zeolite crystals has been developed to be a novel and efficient approach to synthesizing carbon nanotubes. The bundles of carbon nanotubes formed inside the nano-channels have a very limited diameter distribution, and the diameter is determined by channel structure of the chosen zeolite crystals. In this research, I focus on the 0.3 nm SWNTs accommodated in the nano-channels of SAPO-11 single crystals. Efforts are made to explore how to grow high-quality SAPO-11 single crystals with both structural perfection and transparent optical quality. After many attempts, we get an empirically optimized recipe to fabricate SAPO-11 single crystals with high quality. Then, SWNTs with 0.3 nm diameter are synt...[ Read more ]

The pyrolysis process of organic molecules accommodated inside porous nanochannels of AlP0₄ zeolite crystals has been developed to be a novel and efficient approach to synthesizing carbon nanotubes. The bundles of carbon nanotubes formed inside the nano-channels have a very limited diameter distribution, and the diameter is determined by channel structure of the chosen zeolite crystals. In this research, I focus on the 0.3 nm SWNTs accommodated in the nano-channels of SAPO-11 single crystals. Efforts are made to explore how to grow high-quality SAPO-11 single crystals with both structural perfection and transparent optical quality. After many attempts, we get an empirically optimized recipe to fabricate SAPO-11 single crystals with high quality. Then, SWNTs with 0.3 nm diameter are synthesized in the obtained SAPO-11 crystals by means of a pyrolysis process where the crystals serve as template. Raman spectroscopy is used to study the characteristics of these SWNTs.

After preparing these 0.3 nm SWNTs@SAPO-11 complex, we attempt to intercalate lithium atoms into this complex to regulate their electronic properties. Based on the theoretical calculations, lithium atoms can enter into three possible sites. Raman spectroscopy is applied to study the charge transfer behavior between lithium atoms and these ultra-small carbon nanotubes. With elevating doping level, the radial breathing mode (RBM) and tangential G band show intensity loss. The Breit-Wigner-Fano (BWF) component of metallic G⁺ mode has an increasing interaction parameter ∣1/q∣ from 0.20 to 0.40, which indicates the density of electronic states at Fermi level increases. All of these variation patterns are identical to those observed for lithium doped 0.4 nm SWNTs. But at the highest doping concentration, no frequency shift occurs in Raman modes, which is quite different from distinct spectral shift measured for lithium doped 0.4 nm SWNTs. This results from the limited saturated doping concentration LiC_2.8 in 0.3 nm SWNTs@SAP0-11 complex in comparison with Li₃C₄ in 0.4 nm SWNTs@SAP0-5 complex.