Wang Yaping, Liu Lulu, Gong Lingshan, Chen Ying, Liu Jinbin
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, China.
J Phys Chem Lett. 2018 Feb 1;9(3):557-562. doi: 10.1021/acs.jpclett.7b03295. Epub 2018 Jan 19.
We report a facile strategy for the transformation of single NIR-emitting AuNPs to dual-NIR-emitting bimetallic Ag@AuNPs based on the robust reactivity toward Ag(I) ions under mild conditions. The reactivities toward Ag(I) ions were found to be significantly different between visible- and NIR-emitting glutathione (GSH)-coated AuNPs: the high GSH surface coverage on the 610 nm-emitting AuNPs resulted in a reversible interaction due to enough surface steric hindrance to resist Ag(I) ions from interaction with the Au(0) core, whereas the low GSH surface coverage on the 810 nm-emitting AuNPs led to both antigalvanic reaction and Ag(I)-carboxylate shell formation on the surface of the AuNPs, which were responsible for the formation of a new emissive center at 705 nm. This strategy was also demonstrated to exhibit excellent generalization toward various NIR-emitting AuNPs with surface chemistries containing carboxyl groups, opening a new pathway of tailoring the optical properties of metallic NPs through surface reactivity.
我们报道了一种简便的策略，即在温和条件下基于对Ag(I)离子的强反应性，将单发射近红外光的金纳米颗粒（AuNPs）转化为双发射近红外光的双金属银@金纳米颗粒（Ag@AuNPs）。研究发现，可见光发射和近红外光发射的谷胱甘肽（GSH）包覆的AuNPs对Ag(I)离子的反应性存在显著差异：在发射610 nm光的AuNPs上，高GSH表面覆盖率由于足够的表面空间位阻阻止Ag(I)离子与Au(0)核相互作用，导致可逆相互作用；而在发射810 nm光的AuNPs上，低GSH表面覆盖率导致AuNPs表面发生自催化反应和形成Ag(I)-羧酸盐壳层，这是在705 nm处形成新发射中心的原因。该策略还被证明对各种具有含羧基表面化学性质的近红外发射AuNPs具有出色的通用性，为通过表面反应性定制金属纳米颗粒的光学性质开辟了一条新途径。
