We demonstrate that colloidal Cu2 - xSe nanocrystals exhibit a well-defined infrared absorption band due to the excitation of positive charge carrier oscillations (i.e., a valence band plasmon mode), which can be tuned reversibly in width and position by varying the copper stoichiometry. The value of x could be incrementally varied from 0 (no plasmon absorption, then a broad peak at 1700 nm) to 0.4 (narrow plasmon band at 1100 nm) by oxidizing Cu 2Se nanocrystals (upon exposure either to oxygen or to a Ce(IV) complex), and it could be incrementally restored back to zero by the addition of a Cu(I) complex. The experimentally observed plasmonic behavior is in good agreement with calculations based on the electrostatic approximation.
Reversible tunability of the near-infrared valence band plasmon resonance in Cu2- xSe nanocrystals / D. Dorfs, T. Hartling, K. Miszta, N.C. Bigall, M.R. Kim, A. Genovese, A. Falqui, M. Povia, L. Manna. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - 133:29(2011), pp. 11175-11180. [10.1021/ja2016284]
Reversible tunability of the near-infrared valence band plasmon resonance in Cu2- xSe nanocrystals
A. Falqui;
2011
Abstract
We demonstrate that colloidal Cu2 - xSe nanocrystals exhibit a well-defined infrared absorption band due to the excitation of positive charge carrier oscillations (i.e., a valence band plasmon mode), which can be tuned reversibly in width and position by varying the copper stoichiometry. The value of x could be incrementally varied from 0 (no plasmon absorption, then a broad peak at 1700 nm) to 0.4 (narrow plasmon band at 1100 nm) by oxidizing Cu 2Se nanocrystals (upon exposure either to oxygen or to a Ce(IV) complex), and it could be incrementally restored back to zero by the addition of a Cu(I) complex. The experimentally observed plasmonic behavior is in good agreement with calculations based on the electrostatic approximation.File | Dimensione | Formato | |
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Reversible Tunability of the Near-Infrared Valence Band Plasmon Resonance in Cu2xSe Nanocrystals JACS.pdf
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