Print Email Facebook Twitter Switching between Plasmonic and Fluorescent Copper Sulfide Nanocrystals Title Switching between Plasmonic and Fluorescent Copper Sulfide Nanocrystals Author van der Stam, W. (TU Delft ChemE/Opto-electronic Materials) Gudjónsdóttir, S. (TU Delft ChemE/Opto-electronic Materials) Evers, W.H. (TU Delft BN/Technici en Analisten; Kavli institute of nanoscience Delft) Houtepen, A.J. (TU Delft ChemE/Opto-electronic Materials) Date 2017-09-20 Abstract Control over the doping density in copper sulfide nanocrystals is of great importance and determines its use in optoelectronic applications such as NIR optical switches and photovoltaic devices. Here, we demonstrate that we can reversibly control the hole carrier density (varying from >1022 cm-3 to intrinsic) in copper sulfide nanocrystals by electrochemical methods. We can control the type of charge injection, i.e., capacitive charging or ion intercalation, via the choice of the charge compensating cation (e.g., ammonium salts vs Li+). Further, the type of intercalating ion determines whether the charge injection is fully reversible (for Li+) or leads to permanent changes in doping density (for Cu+). Using fully reversible lithium intercalation allows us to switch between thin films of covellite CuS NCs (Eg = 2.0 eV, hole density 1022 cm-3, strong localized surface plasmon resonance) and low-chalcocite CuLiS NCs (Eg = 1.2 eV, intrinsic, no localized surface plasmon resonance), and back. Electrochemical Cu+ ion intercalation leads to a permanent phase transition to intrinsic low-chalcocite Cu2S nanocrystals that display air stable fluorescence, centered around 1050 nm (fwhm â145 meV, PLQY ca. 1.8%), which is the first observation of narrow near-infrared fluorescence for copper sulfide nanocrystals. The dynamic control over the hole doping density and fluorescence of copper sulfide nanocrystals presented in this work and the ability to switch between plasmonic and fluorescent semiconductor nanocrystals might lead to their successful implementation into photovoltaic devices, NIR optical switches and smart windows. To reference this document use: http://resolver.tudelft.nl/uuid:cd3d7e84-d478-4ac0-9c2a-4a23611473ef DOI https://doi.org/10.1021/jacs.7b07788 ISSN 0002-7863 Source Journal of the American Chemical Society, 139 (37), 13208-13217 Part of collection Institutional Repository Document type journal article Rights © 2017 W. van der Stam, S. Gudjónsdóttir, W.H. Evers, A.J. Houtepen Files PDF jacs.7b07788.pdf 5.08 MB Close viewer /islandora/object/uuid:cd3d7e84-d478-4ac0-9c2a-4a23611473ef/datastream/OBJ/view