Charge Transfer Structure鈥揜eactivity Dependence of Fullerene鈥揝ingle-Walled Carbon Nanotube Heterojunctions

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• 作者：Andrew J. Hilmer ; Kevin Tvrdy ; Jingqing Zhang ; Michael S. Strano
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：August 14, 2013
• 年：2013
• 卷：135
• 期：32
• 页码：11901-11910
• 全文大小：623K
• 年卷期：v.135,no.32(August 14, 2013)
• ISSN：1520-5126

文摘

Charge transfer at the interface between single-walled carbon nanotubes (SWCNTs) of distinct chiral vectors and fullerenes of various molecular weights is of interest both fundamentally and because of its importance in emerging photovoltaic and optoelectronic devices. One approach for generating isolated, discretized fullerene鈥揝WCNT heterojunctions for spectroscopic investigation is to form an amphiphile, which is able to disperse the latter at the single-SWCNT level in aqueous solution. Herein, we synthesize a series of methanofullerene amphiphiles, including derivatives of C₆₀, C₇₀, and C₈₄, and investigated their electron transfer with SWCNT of specific chirality, generating a structure鈥搑eactivity relationship. In the cases of two fullerene derivatives, lipid鈥揅₆₁鈥損olyethylene glycol (PEG) and lipid鈥揅₇₁鈥揚EG, band gap dependent, incomplete quenching was observed across all SWCNT species, indicating that the driving force for electron transfer is small. This is further supported by a variant of Marcus theory, which predicts that the energy offsets between the nanotube conduction bands and the C₆₁ and C₇₁ LUMO levels are less than the exciton binding energy in SWCNT. In contrast, upon interfacing nanotubes with C₈₅ methanofullerene, a complete quenching of all semiconducting SWCNT is observed. This enhancement in quenching efficiency is consistent with the deeper LUMO level of C₈₅ methanofullerene in comparison with the smaller fullerene adducts, and suggests its promise as for SWCNT鈥揻ullerene heterojunctions.