Generating plasmonic heterostructures by cation exchange and redox reactions of covellite CuS nanocrystals with Au3+ ions. Issue 6 (23rd January 2018)

• Record Type: Journal Article
• Authors: Hu, Chao; Chen, Wenhui; Xie, Yi; Verma, Santosh Kumar; Destro, Priscila; Zhan, Gang; Chen, Xingzhu; Zhao, Xiujian; Schuck, P. James; Kriegel, Ilka; Manna, Liberato
• Is Part Of: Nanoscale. Volume 10:Issue 6(2018)
• Page Start: 2781
• Page End: 2789
• Publication Date: 2018-01-23
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c7nr07283j
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Generating heterostructures with tunable LSPRs by cation exchange and redox reactions of CuS NCs with Au 3+, in the presence or in the absence of oleylamine (OM) and ascorbic acid (AA). Abstract : We demonstrate the fabrication of various types of heterostructures, including core–shells and dimers. This is achieved by reacting platelet-shaped covellite (CuS) nanocrystals (NCs) with Au 3+ ions under various reaction conditions: the exposure of CuS NCs to Au 3+ ions, in the presence or in the absence of ascorbic acid (AA), leads to the formation of CuS@Au core–shell nanostructures; the reaction of CuS NCs with Au 3+ ions in the presence of oleylamine (OM) leads to the formation of CuS@Au2 S; the presence of both OM and AA leads to the formation of Au/CuS dimers. Depending on which condition is chosen, either cation exchange (CE) between gold and copper ions is predominant (leading to amorphous Au2 S) or the reduction of Au 3+ leads to the nucleation of metallic Au domains (which are operated by the AA). In the heterostructures achieved by CE, the Au2 S shell is almost entirely amorphous, and can be converted to polycrystalline upon electron beam irradiation. Finally, when both oleylamine and AA are present in the reaction environment, Au/CuS dimers are formed due to the reduction of Au 3+ to metallic Au domains which nucleate on top of the CuS seeds. The experimental dual plasmonic bands of the CuS@Au core–shells and Au/CuS dimers are in agreement with the theoretical optical simulations. The procedures described here enable the synthesis of core–shell nanostructures with tunable localized surface plasmon resonances (LSPRs) in the near-infrared (NIR) region, and of plasmonic metal/semiconductor heterostructures with LSPRs in both the NIR and the visible regions.