Department of Physics, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong SAR, China.
HKBU Institute of Research and Continuing Education, 9F, The Industrialization Complex of Shenzhen Virtual University Park, No. 2 Yuexing Third Road, South Zone, Hi-tech Industrial Park, Nanshan District, Shenzhen, Guangdong, 518057, China.
Small. 2020 Feb;16(6):e1906048. doi: 10.1002/smll.201906048. Epub 2020 Jan 21.
Metallic chiral nanoparticles (CNPs) with a nominal helical pitch (P) of sub-10 nm contain inherent chirality and are promisingly applied to diverse prominent enantiomer-related applications. However, the sub-wavelength P physically results in weak optical activity (OA) to prohibit the development of these applications. Herein, a facile method to amplify the CNPs' OA by alloying the host CNPs with metals through a three-step layer-by-layer glancing angle deposition (GLAD) method is devised. Promoted by the GLAD-induced heating effect, the solute metallic atoms diffuse into the host CNPs to create binary alloy CNPs. Chiral alloying not only induces the plasmonic OA of the diffused solute and the created alloys but also amplifies that of the host CNPs, generally occurring for alloying Ag CNPs with diverse metals (including Cu, Au, Al, and Fe) and alloying Cu CNPs with Ag. Furthermore, the chiral alloying leads to an enhancement of refractive index sensitivity of the CNPs. The alloy CNPs with amplified plasmonic OA pave the way for potentially developing important chirality-related applications in the fields of heterogeneous asymmetric catalysis, enantiodifferentiation, enantioseparation, biosensing, and bioimaging.
具有亚 10nm 名义螺旋节距（P）的金属手性纳米颗粒（CNP）具有内在手性，有望应用于各种突出的对映体相关应用。然而，亚波长 P 导致弱旋光活性（OA），从而限制了这些应用的发展。在此，通过三步逐层掠入射沉积（GLAD）方法，设计了一种通过将主体 CNP 与金属合金化来放大 CNP 的 OA 的简便方法。受 GLAD 诱导的加热效应的推动，溶质金属原子扩散到主体 CNP 中以形成二元合金 CNP。手性合金化不仅诱导扩散溶质和所形成的合金的等离子体 OA，而且还放大了主体 CNP 的 OA，通常发生在将 Ag CNP 与各种金属（包括 Cu、Au、Al 和 Fe）合金化以及将 Cu CNP 与 Ag 合金化时。此外，手性合金化导致 CNP 的折射率灵敏度增强。具有放大的等离子体 OA 的合金 CNP 为在异相不对称催化、对映体区分、对映体分离、生物传感和生物成像等领域中开发重要的手性相关应用铺平了道路。
