Synthesis and Spectroscopy of PbSe Fused Quantum-Dot Dimers

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• 作者：Barbara K. Hughes ; Jeffrey L. Blackburn ; Daniel Kroupa ; Andrew Shabaev ; Steven C. Erwin ; Alexander L. Efros ; Arthur J. Nozik ; Joseph M. Luther ; Matthew C. Beard
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：March 26, 2014
• 年：2014
• 卷：136
• 期：12
• 页码：4670-4679
• 全文大小：734K
• 年卷期：v.136,no.12(March 26, 2014)
• ISSN：1520-5126

文摘

We report the synthesis and characterization of Pb-chalcogenide fused quantum-dot (QD) dimer structures. The resulting QD dimers range in length from 6 to 16 nm and are produced by oriented attachment of single QD monomers with diameters of 3.1鈥?.8 nm. QD monomers with diameters exceeding about 5 nm appear to have the greatest affinity for QD dimer formation and, therefore, gave the greatest yields of fused structures. We find a new absorption feature in the first exciton QD dimer spectra and assign this to a splitting of the 8-fold degenerate 1S-level. The dimer splitting increases from 50 to 140 meV with decrease of the QD-monomer size, and we present a mechanism that accounts for this splitting. We also demonstrate the possibility of fusing two QDs with different sizes into a heterostructure.