Optically Activated Functionalization Reactions in Si Quantum Dots

Fernando A. Reboredo,* Eric Schwegler, and Giulia Galli
Contribution from the Lawrence Livermore National Laboratory, Livermore, California 94588
J. Am. Chem. Soc., 2003, 125 (49), pp 15243–15249
DOI: 10.1021/ja035254+
Publication Date (Web): November 14, 2003
Copyright © 2003 American Chemical Society
*

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

, reboredo1@llnl.gov

Abstract

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Using ab initio calculations, we have studied the influence of optical activation on functionalization reactions of silicon quantum dots with unsaturated hydrocarbons. We find that the energy barrier for the replacement of silicon−hydrogen with silicon−carbon bonds is dramatically reduced if the silicon dot is optically excited. These results provide an explanation for recent experiments on optically excited porous silicon. In addition, our calculations point at the existence of an intermediate spin-polarized state formed by the dot and an alkene or alkyne, upon relaxation after absorbing a photon. This state could be detected experimentally, by, for example, electron spin resonance measurements. Based on the results of our calculations as a function of the dot size, varied from 0.8 to 1.5 nm, we propose that light activated reactions could be used to functionalize and size select silicon quantum dots at the same time.

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History

  • Published In Issue December 10, 2003
  • Received March 20, 2003

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