title: Reversible tunability of the near-infrared valence band plasmon resonance in Cu(2-x)Se nanocrystals.
abstract: We demonstrate that colloidal Cu(2-x)Se 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(2)Se 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.
authors: Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
authors: Dirk
authors: D
authors: Dorfs
authors: Thomas
authors: T
authors: Härtling
authors: Karol
authors: K
authors: Miszta
authors: Nadja C
authors: NC
authors: Bigall
authors: Mee Rahn
authors: MR
authors: Kim
authors: Alessandro
authors: A
authors: Genovese
authors: Andrea
authors: A
authors: Falqui
authors: Mauro
authors: M
authors: Povia
authors: Liberato
authors: L
authors: Manna