title: Effect of Substituents and Initial Degree of Functionalization of Alkylated Single-Walled Carbon Nanotubes on Their Thermal Stability and Photoluminescence Properties.
abstract: Alkylated single-walled carbon nanotubes (SWNTs) have been thermally treated to determine the influence of substituents and the degree of functionalization on their thermal stability and photoluminescence (PL) properties. Alkylated SWNTs were prepared by treating SWNTs with sodium naphthalenide and alkyl bromide. The defunctionalization of the alkylated SWNTs was monitored by absorption and Raman spectra. Selective recovery of the characteristic absorption and radial breathing mode peaks was observed during the thermal treatment, which indicates that the thermal stability of the alkylated SWNTs decreases with increases in SWNT diameter and degree of functionalization. n-Butylated and phenethylated SWNTs showed higher thermal stability than sec-butylated and benzylated SWNTs for a similar degree of functionalization, respectively. The diameter selectivity and effect of substituents on the thermal elimination reaction were confirmed by density functional theory. In addition, it was shown that the initial degree of functionalization of the alkylated SWNTs, with the alkyl group and degree of functionalization being kept constant after thermal treatment, strongly affects their PL properties; Stokes shift, and PL peak intensity.
authors: Department of Chemistry, Tokyo Gakugei University, Tokyo, 184-8501, Japan.
authors: Yutaka
authors: Y
authors: Maeda
authors: Department of Chemistry, Tokyo Gakugei University, Tokyo, 184-8501, Japan.
authors: Yuya
authors: Y
authors: Takehana
authors: Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto, 606-8103, Japan.
authors: Jing-Shuang
authors: JS
authors: Dang
authors: Department of Chemistry, Tokyo Gakugei University, Tokyo, 184-8501, Japan.|Department of Chemistry, Faculty of Science, Josai University, Saitama, 350-0295, Japan.
authors: Mitsuaki
authors: M
authors: Suzuki
authors: Department of Chemistry, Tokyo Gakugei University, Tokyo, 184-8501, Japan.
authors: Michio
authors: M
authors: Yamada
authors: Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto, 606-8103, Japan.
authors: Shigeru
authors: S
authors: Nagase
keywords: density functional calculations; luminescence; nanotubes; substituent effects; thermal stability