TY - JOUR
T1 - Binary Chiral Nanoparticles Exhibit Amplified Optical Activity and Enhanced Refractive Index Sensitivity
AU - Yang, Lin
AU - Nandi, Proloy
AU - Ma, Yicong
AU - Liu, Junjun
AU - Mirsaidov, Utkur
AU - Huang, Jeffery
N1 - Funding Information:
L.Y. and P.N. contributed equally to this work. The authors gratefully acknowledge Benson Leung (Physics, HKBU) for technical support with TEM, and Winnie Wu (IAM, HKBU) for technical support with XRD and XPS. This work was financially supported by NSFC/91856127, GRF/12200118, FRG2/17‐18/058, and the Singapore National Research Foundation's Competitive Research Program funding (NRF‐CRP16‐2015‐05).
PY - 2020/2/1
Y1 - 2020/2/1
N2 - 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.
AB - 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.
KW - binary alloys
KW - chiral nanoparticles
KW - glancing angle deposition
KW - optical activity
KW - refractive index sensitivity
UR - http://www.scopus.com/inward/record.url?scp=85078664497&partnerID=8YFLogxK
U2 - 10.1002/smll.201906048
DO - 10.1002/smll.201906048
M3 - Journal article
C2 - 31961482
AN - SCOPUS:85078664497
SN - 1613-6810
VL - 16
JO - Small
JF - Small
IS - 6
M1 - 1906048
ER -