Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
J Am Chem Soc. 2011 Jul 27;133(29):11175-80. doi: 10.1021/ja2016284. Epub 2011 Jul 6.
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.
我们证明了胶体 Cu(2-x)Se 纳米晶体由于正电荷载流子振荡（即价带等离子体模式）的激发而表现出明确的红外吸收带，通过改变铜化学计量比可以可逆地调节其宽度和位置。通过氧化 Cu(2)Se 纳米晶体（暴露于氧气或 Ce(IV) 配合物），x 值可以从 0（无等离子体吸收，然后在 1700nm 处出现宽峰）逐渐增加到 0.4（在 1100nm 处出现窄等离子体带），并且通过添加 Cu(I) 配合物可以逐渐恢复到零。实验观察到的等离子体行为与基于静电近似的计算吻合良好。
