Bao Haoming, Zhang Hongwen, Zhou Le, Fu Hao, Liu Guangqiang, Li Yue, Cai Weiping
Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics , Chinese Academy of Sciences , Hefei 230031 , P. R. China.
University of Science and Technology of China , Hefei 230026 , P. R. China.
ACS Appl Mater Interfaces. 2019 Aug 7;11(31):28145-28153. doi: 10.1021/acsami.9b05878. Epub 2019 Jul 23.
A facile and general strategy is presented for homogenous and ultrathin metal sulfide wrapping on plasmonic metal (PM) nanoparticles (NPs) based on a thiourea-induced isotropic shell growth. This strategy is typically implemented just via adding the thiourea into pre-formed PM colloidal solutions containing target metal ions. The validity of this strategy is demonstrated by taking the wrapped NPs with Au core and CuS shell or Au@CuS NPs as an example. They are successfully fabricated via adding the thiourea and Cu solutions into pre-formed Au NP colloidal solution. The CuS shell layer is highly homogenous (<10% in relative standard deviation of shell thickness), regardless of the NPs' shape or curvature. The shell thickness can be controlled from tens down to 0.5 nm just by the addition of different amounts of shell precursors. The formation of the shell layer on the Au NPs can be attributed to the alternative deposition of Cu and S ions on the thiourea-modified surface of Au NPs in the solution, which induces the isotropic shell growth. Further, this strategy is of good universality. Many other sulfide-wrapped PM NPs, such as Ag@CuS, Au@PtS, Au@HgS, Ag@AgS NPs, and Ag@CuS nanorods, have been successfully obtained with homogeneous and ultrathin shells. Importantly, such ultrathin sulfide-wrapped PM NPs can be used for surface enhanced Raman scattering (SERS)-based detection of trace heavy-metal ions with strong anti-interference via the ion exchange process between the metal sulfide shell and heavy-metal ions. This study provides a simple and controllable route for wrapping the homogenous and ultrathin sulfide layers on the PM NPs, and such wrapped NPs have good practical applications in the SERS-based detection of trace heavy-metal ions.
基于硫脲诱导的各向同性壳层生长，提出了一种在等离子体金属（PM）纳米颗粒（NP）上均匀包覆超薄金属硫化物的简便通用策略。该策略通常只需将硫脲添加到含有目标金属离子的预制PM胶体溶液中即可实现。以具有金核和硫化铜壳层的包覆NP（即Au@CuS NPs）为例，证明了该策略的有效性。通过将硫脲和铜溶液添加到预制的金NP胶体溶液中，成功制备了它们。无论NP的形状或曲率如何，硫化铜壳层都高度均匀（壳层厚度的相对标准偏差<10%）。只需添加不同量的壳层前驱体，壳层厚度就可以从几十纳米控制到0.5纳米。金NP上壳层的形成可归因于溶液中铜离子和硫离子在硫脲修饰的金NP表面交替沉积，从而诱导各向同性壳层生长。此外，该策略具有良好的通用性。许多其他硫化物包覆的PM NP，如Ag@CuS、Au@PtS、Au@HgS、Ag@AgS NPs和Ag@CuS纳米棒，都已成功获得具有均匀超薄壳层的产物。重要的是，这种超薄硫化物包覆的PM NP可用于基于表面增强拉曼散射（SERS）的痕量重金属离子检测，通过金属硫化物壳层与重金属离子之间的离子交换过程具有很强的抗干扰能力。这项研究为在PM NP上包覆均匀超薄硫化物层提供了一条简单可控的途径，并且这种包覆的NP在基于SERS的痕量重金属离子检测中具有良好的实际应用。
