Toward Combining Graphene and QDs: Assembling CdTe QDs to Exfoliated Graphite and Nanographene in Water

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• 作者：Georgios Katsukis ; Jenny Malig ; Christian Schulz-Drost ; Susanne Leubner ; Norbert Jux ; Dirk M. Guldi
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：March 27, 2012
• 年：2012
• 卷：6
• 期：3
• 页码：1915-1924
• 全文大小：583K
• 年卷期：v.6,no.3(March 27, 2012)
• ISSN：1936-086X

文摘

Herein, we report for the first time on a full-fledged investigation of water-soluble CdTe quantum dots (QD) that are immobilized onto exfoliated graphite (EG) and/or nanographene (NG). Particular emphasis was placed on a top-down preparation of stable aqueous dispersions鈥搒tarting from natural graphite rather than graphene oxide鈥搘hile preserving the intrinsic properties of graphene. To this end, we circumvented the harsh conditions commonly employed for the pre-exfoliation (i.e., Hummers method). First, a hydrophobic鈥揾ydrophobic/蟺鈥撓€ stacking motif was tested between EG and pyrene, to which QDs are covalently attached (QD-pyrene). Second, we employed the combination of hydrophobic鈥揾ydrophobic/蟺鈥撓€ stacking and electrostatic interactions to build up hierarchical structures composed of NG, positively charged pyrene (pyrene⁺), and negatively charged QDs. The novel nanohybrids鈥擰D-pyrene/EG and QD/pyrene⁺/NG鈥攚ere characterized with specific emphasis on electron-transfer chemistry. In fact, both assays provide kinetic and spectroscopic evidence that support electron transfer dynamics that vary, however, between EG and NG as a reflection of the different degree of graphite exfoliation.

Keywords:

nanographene; exfoliated graphite; CdTe quantum dots; time-resolved spectroscopy; electron transfer