Ultrafast Charge Separation in Multiexcited CdSe Quantum Dots Mediated by Adsorbed Electron Acceptors

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• 作者：Victor V. Matylitsky*^† ; ; Lars Dworak^† ; ; Vladimir V. Breus^‡ ; ; Thomas Basch^‡ ; ; Josef Wachtveitl^† ;
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：February 25, 2009
• 年：2009
• 卷：131
• 期：7
• 页码：2424-2425
• 全文大小：150K
• 年卷期：v.131,no.7(February 25, 2009)
• ISSN：1520-5126

文摘

Ultrafast ET with a characteristic time constant of 70 fs between CdSe QDs (mean radii of 1.4 nm) photoexcited in the lowest 1S electron state (λ_exc = 539 nm), and the molecular electron acceptor MV²⁺ adsorbed on the QD surface was observed. The photophysics of such a system was investigated by time-resolved transient absorbance spectroscopy in the UV−visible spectral region. Our studies for the coupled system as a function of excitation intensity at λ_exc = 387 nm show that the ET processes compete efficiently with Auger recombination in CdSe QDs and at least 4 e−h pairs can be separated by ET to the electron acceptor MV²⁺.