Modulation of Cu2‿i>xS Nanocrystal Plasmon Resonance through Reversible Photoinduced Electron Transfer

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• 作者：Rabeka Alam ; Molly Labine ; Christopher J. Karwacki ; Prashant V. Kamat
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：February 23, 2016
• 年：2016
• 卷：10
• 期：2
• 页码：2880-2886
• 全文大小：385K
• ISSN：1936-086X

文摘

Copper sulfide (Cu_2–xS) nanocrystals with nonstoichiometric composition exhibit plasmon resonance in the near-infrared region. Compositional changes and varying electron density markedly affect the position and intensity of the plasmon resonance. We report a photochemically induced phenomenon of modulating the plasmon resonance in a controlled fashion. As photogenerated reduced methyl viologen radicals transfer electrons to Cu_2–xS in inert solutions, we observe a decrease in localized surface plasmon resonance (LSPR) absorbance at 1160 nm. Upon exposure to air, the plasmon resonance band recovers as stored electrons are scavenged away by oxygen. This cycle of electron charge and discharge of Cu_2–xS nanocrystals is reversible and can be repeated through photoirradiation in N₂ saturated solution followed by exposure of the suspension to air. The spectroscopic studies that provide mechanistic insights into the reversible charging and discharging of plasmonic Cu_2–xS are discussed.