Hole Scavenging and Electron–Hole Pair Photoproduction Rate: Two Mandatory Key Factors to Control Single-Tip Au–CdSe/CdS Nanoheterodimers

• Published in: ACS nano Vol. 15; no. 9; pp. 15328 - 15341
• Main Authors: Hao, Junjie, Liu, Haochen, Wang, Kai, Sun, Xiao Wei, Delville, Jean-Pierre, Delville, Marie-Helene
• Format: Journal Article
• Language: English
• Published: American Chemical Society 28.09.2021
• Subjects: CdSe/CdS; hetero-nanodimers; laser; single-tip gold nanodots; hole scavenger; photodeposition
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.1c06383

Metal/semiconductor hetero-nanostructures are now considered as benchmark functional nanomaterials for many light-driven applications. Using laser-driven photodeposition to control growth of gold nanodots (NDs) onto CdSe/CdS dot-in-rods (DRs), we show that the addition of a dedicated hole scavenger (MeOH) is the cornerstone to significantly reduce to less than 3.5% the multiple-site nucleation and 2.5% the rate of gold-free DRs. This means, from a synthetic point of view, that rates up to 90% of single-tip DRs can be reproducibly achieved. Moreover, by systematically varying this hole scavenger concentration and the Au/DRs ratio on the one hand, and the irradiation intensity and the time exposure on the other hand, we explain how gold deposition switches from multisite to single-tipped and how the growth and final size of the single photodeposited ND can be controlled. A model also establishes that the results obtained based on these different varying conditions can be merged onto a single “master behavior” that summarizes and predicts the single-tip gold ND growth onto the CdSe/CdS DRs. We eventually use data from the literature on growth of platinum NDs onto CdS nanorods by laser-deposition to extend our investigation to another metal of major interest and strengthen our modeling of single metallic ND growth onto II–VI semiconducting nanoparticles. This demonstrated strategy can raise a common methodology in the synthesis of single-tip semiconductor–metal hybrid nanoheterodimers (NHDs), leading to advanced nanoparticles architectures for applications in areas as different as photocatalysis, hydrogen production, photovoltaics, and light detection.