Centre d'Elaboration des Matériaux et d'Etudes Structurales, UPR-8011 CNRS, University of Toulouse, Toulouse, France.
Small. 2012 Jul 9;8(13):2045-52. doi: 10.1002/smll.201102410. Epub 2012 Apr 17.
The selective excitation of fullerenes encapsulated in single-walled carbon nanotubes (SWCNTs) is carried out by irradiating them using a UV laser, the wavelength of which corresponds exactly to their maximum of absorption. Under such conditions, fullerenes strongly absorb the laser energy, open, and break, while the containing SWCNT merely acts as both a nanoreactor and a mold which is only weakly heated by the laser. The containing tube confines the fullerene fragments, promotes their reconstruction into an inner tube, and protects them from air oxidation. This leads to the overall formation of double-walled carbon nanotubes (DWCNTs). The transformation is found to strongly depend on the laser irradiance and dose. This proves that the related mechanism is a multiphoton photolysis, different from the previous heat-induced transformation attempts found in the literature, whether the heat is produced by means of a thermostat, infrared laser, or nonresonant UV laser. The actual peapod-to-DWCNT transformation is monitored by Raman spectroscopy and high-resolution transmission electron microscopy.
采用与富勒烯最大吸收峰波长完全匹配的紫外激光选择性激发单壁碳纳米管（SWCNT）内的富勒烯，在这种条件下，富勒烯强烈吸收激光能量，发生开环和断裂，而包含富勒烯的 SWCNT 仅作为纳米反应器和模具，仅被激光弱加热。包含管限制了富勒烯碎片，促进了它们在内部管中的重建，并保护它们免受空气氧化。这导致了双壁碳纳米管（DWCNT）的整体形成。发现这种转变强烈依赖于激光辐照度和剂量。这证明相关机制是多光子光解，与文献中以前发现的热诱导转变尝试不同，无论热是通过恒温器、红外激光还是非共振紫外激光产生的。实际的pea pod 到 DWCNT 的转变通过拉曼光谱和高分辨率透射电子显微镜进行监测。
