Controlled Synthesis and Flexible Self-Assembly of Monodisperse Au@Semiconductor Core/Shell Hetero-Nanocrystals into Diverse Superstructures

Abstract

Monodisperse nonepitaxially grown Au@MX (MX = Ag 2 S, ZnS, or CdS) core/shell hetero-nanocrystals (HNCs) with controlled crystallinity, composition, anisotropically shaped Au cores but isotropic overall morphologies were successfully prepared. By using C18 acid/alkali co-capping surface ligands, the as-prepared Au@MX HNCs can selfassemble into large-scale two-dimensional monolayer and three-dimensional multilayer superlattices (SLs) on both flexible (graphene) and rigid (Si wafer or glass) substrates. Moreover, unprecedented binary nanocrystal SLs can be achieved through synergistic self-assembly of Au@MX HNCs together with Au NCs (or CdS NCs) into different intricate patterns. Experimental evidence and finite-element method theoretical simulations indicate that the Au@CdS HNC SL film taking up a closest-packing mode has a rate of photocurrent generation much higher than that of its disordered−assembled counterpart, probably because of the enhanced plasmon−exciton coupling permitted by the large-scale ordered nanopatterning.

A general ligand-assisted self-assembly approach to crystalline mesoporous metal oxides

“…Suib et al reported an inverse micelle synthesis system to prepare mesoporous metal oxides 14 . Mesoporous materials with diverse morphologies and tunable pore sizes have been prepared by controlling the synthesis conditions and the properties of the template molecules based on soft templating 15,16 . This approach is flexible and effective for largescale synthesis.…”

Preparation of ZnS@In2S3 Core@shell Composite for Enhanced Photocatalytic Degradation of Gaseous o-Dichlorobenzene under Visible Light

“…However, its wide band gap and high recombination rate of photo-generated charges often lead to low quantum yield in the photocatalytic reactions. To address the key issue of low quantum yield, many methods, such as noble metal deposition 7,8 , element doping 9 and semiconductor coupling 10,11 , have been extensively studied and applied in recent years 12–15 . Among these approaches, coupling with other semiconductors for forming the composites is one of the most effective ways to improve the separation efficiency of photo-generated charges, which could also take full advantage of solar spectrum, compared with the individual material 16,17 .…”

Colloid‐Interface‐Assisted Laser Irradiation of Nanocrystals Superlattices to be Scalable Plasmonic Superstructures with Novel Activities

“…Interface, formed between two different phases, can provide interfacial interactions for application ranging from chemical synthesis of shaped controlled NCs to self‐assembly of NCs to be SLs . For example, noble metal NCs, semiconductor NCs, as well as the nonepitaxial growth core/shell NCs can be assembled into monolayer SLs, multilayer SLs, and even binary NCs SLs by the aid of the interfaces . Among these SLs, due to the SPR effect of Au NCs, the Au‐based SLs might react with the SPR‐related light that leads to the hot spots generation.…”

“…Due to the existence of strong SPR effect from Au core, the hot spots may be generated at the interparticle gaps within the core/shell NCs assembly by the 532 nm laser irradiation. The monodisperse Au@CdS NCs were synthesized by our published nonepitaxial strategy and the SLs monolayer could be obtained and deposited onto the carbon substrates by a dip‐coating method …”