Copper sulfide (Cu2-xS) nanocrystals with nonstochiometric composition exhibits plasmon resonance in the near infrared region. Compositional changes and varying electron density markedly affects the position and intensity of the plasmon resonance. We report a simple photochemical phenomenon of transferring electrons to Cu2-xS and modulating the plasmon resonance in a controlled way. As photogenerated methyl viologen radicals transfer electrons to Cu2-xS in inert solutions, we observe a decrease in localized surface plasmon resonance (LSPR) absorbance at 1158 nm. Upon exposure to air the plasmon resonance band recovers as sored electron are scavenged away by oxygen. This cycle of charge and discharge of Cu2-xS nanocrystals is reversible and can be repeated through photoirradiation in N2 saturated solution and then exposing to air. The spectroscopic study that provides mechanistic insights into the reversible charging and discharging of plasmonic Cu2-xS will be discussed.

Photoinduced electron transfer as a means to modulate the plasmon resonance of Cu2-xS quantum dots

251st National Meeting (2016)

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