Controlling the Optical Properties of Inorganic Nanoparticles

Authors

  • Gregory D. Scholes

    Corresponding author
    1. Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 (Canada)
    2. Institute for Optical Sciences, and Centre for Quantum, Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 (Canada)
    • Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 (Canada).===

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  • The Natural Sciences and Engineering Research Council of Canada is gratefully acknowledged for support of this research. G. D. S. acknowledges the support of an E. W. R. Steacie Memorial Fellowship. I thank each of my students and postdocs for their important contributions to the work reviewed here. In particular I thank Dr. M. A. Hines, Dr. S. Nair, and Dr. S. Kumar for their nanocrystal innovations. I thank Ms. V. M. Huxter, Ms. T. Mirkovic, and Ms. C. Y. Wong for their comments on the manuscript.

Abstract

The sophistication with which we can now prepare and characterize inorganic nanoparticles has inspired new areas of research into the fundamental properties and applications of these fascinating nanoscale systems. In this article some of the recent ideas concerning control of their optical properties are examined and explained, focusing on semiconductor nanocrystals. It is known that the optical properties of nanocrystals can be size-tunable, but it is less obvious how shape matters. To explain how size as well as shape matters, the electronic structure of nanocrystals is sketched in relatively simple terms, leading to an introduction to deeper concepts at the heart of spectroscopy such as the exciton fine structure. The exciton fine structure states, although obscured by inhomogeneous line broadening, dictate selection rules for optical excitation. These viewpoints are compared and contrasted to well-established principles in molecular spectroscopy that provide inspiration as well as perspective. The control of optical poperties is founded on our ability to prepare good quality colloidal particles. Recent advances in nanocrystal shape control are described. The current status of heterostructures is examined, with an emphasis on charge separation in CdSe–CdTe nanorods.

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