Toward Combining Graphene and QDs: Assembling CdTe QDs to Exfoliated Graphite and Nanographene in Water
Toward Combining Graphene and QDs: Assembling CdTe QDs to Exfoliated Graphite and Nanographene in Water
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DOI：
10.1021/nn204700z
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发表时间：
2012-03-01
期刊：
影响因子：
17.1
通讯作者：
Guldi, Dirk M.
中科院分区：
文献类型：
--
作者：
Katsukis, Georgios;Malig, Jenny;Guldi, Dirk M.
在此，我们首次报告了对固定在剥离石墨（EG）和/或纳米石墨烯（NG）上的水溶性量子点（QD）的全面研究。特别强调从天然石墨而不是氧化石墨烯开始，自上而下制备稳定的水分散体，同时保留石墨烯的固有特性。为此，我们规避了预剥离常用的恶劣条件（即，首先，在 EG 和芘之间测试了疏水-疏水/pi-pi 堆积基序，QD 与该基序共价连接（QD-芘）。其次，我们采用疏水-疏水/pi-pi 堆积和静电相互作用的组合来构建由 NG、带正电的芘（芘（+））和带负电的 QD 组成的分层结构。 QD/芘(+)/NG-的特征特别强调电子转移化学。事实上，两种测定都提供了支持电子转移动力学的动力学和光谱证据，然而，EG 和 NG 之间的电子转移动力学不同，反映了石墨剥落的不同程度。
Herein, we report for the first time on a full-fledged investigation of water-soluble (die 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-starting from natural graphite rather than graphene oxide-while 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-hydrophobic/pi-pi stacking motif was tested between EG and pyrene, to which QDs are covalently attached (QD-pyrene). Second, we employed the combination of hydrophobic-hydrophobic/pi-pi stacking and electrostatic interactions to build up hierarchical structures composed of NG, positively charged pyrene (pyrene(+)), and negatively charged QDs. The novel nanohybrids-QD-pyrene/EG and QD/pyrene(+)/NG-were 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.