Au-Cu2-xTe Plasmonic Heteronanostructure Photoelectrocatalysts

Heteronanotrimers by Selective Photodeposition of Gold Nanodots on Janus-Type Cu2‒ xS/CuInS2 Heteronanocrystals

This study focuses on the development of environmentally friendly Au-Cu2-xS/CuInS2 heteronanotrimers. The chosen strategy relies on the laser photodeposition of a single gold nanodot (ND) onto Janus Cu2- xS/CuInS2 heteronanocrystals (HNCs). This method offers precise control over the number, location, and size (5 to 8 nm) of the Au NDs by adjusting laser power for the career production, concentration of hole scavenger for charge equilibration in redox reactions, and gold precursor concentration, and exposure time for the final ND size. The photoreduction of gold ions onto HNCs starts systematically at the Cu2- xS tip. The Au deposition then depends on the CuInS2 segment length. For short HNCs, stable Au-Cu2- xS/CuInS2 heteronanotrimers form, while long HNCs undergo a secondary photo-induced step: the initial Au ND is progressively oxidized, with concomitant deposition of a second gold ND on the CuInS2 side, to yield Au2S-Cu2- xS/CuInS2-Au heteronanotrimers. Results are rationalized by quantitative comparison with a model that describes the growth kinetics of NDs and Au-Cu2- xS transformation and emphasizes the importance of charge separation in predicting selective deposition in heteronanotrimer production. The key parameter controlling Au-Cu2‒ xS/CuInS2 HNCs is the photoinduced electric field gradient generated by charge separation, which is tailored by controlling the CuInS2 segment size.

Aqueous Topological Synthesis of Au@semiconductor Core-Shell Nanocrystals with Morphology and Composition Engineering

Core-shell nanocrystals (C-S NCs) are an essential class of materials whose structural engineering has attracted wide attention due to their tunable optical and electrical properties, especially noble metal@semiconductor (NMS) C-S NCs with flexible plasmon-exciton coupling. Due to their diverse critical applications, especially aqueous biological applications, herein we propose an aqueous topological strategy enabled by cation exchange reactions (CER) to synthesize various plasmonic Au@semiconductor C-S NCs, in which environmentally friendly triphenylphosphine (TPP) is used as an initiator instead of inflammable tributyl phosphine (TBP). The introduction of the milder, solid TPP facilitated a new aqueous CER strategy for synthesizing Au@semiconductor NCs with tailored chalcogenide compositions and morphologies. For example, the as-synthesized Au@ZnS C-S NRs had better absorption and biocompatibility and exhibited excellent photodynamic therapy efficacy.

Rich Landscape of Colloidal Semiconductor-Metal Hybrid Nanostructures: Synthesis, Synergetic Characteristics, and Emerging Applications

Nanochemistry provides powerful synthetic tools allowing one to combine different materials on a single nanostructure, thus unfolding numerous possibilities to tailor their properties toward diverse functionalities. Herein, we review the progress in the field of semiconductor-metal hybrid nanoparticles (HNPs) focusing on metal-chalcogenides-metal combined systems. The fundamental principles of their synthesis are discussed, leading to a myriad of possible hybrid architectures including Janus zero-dimensional quantum dot-based systems and anisotropic quasi 1D nanorods and quasi-2D platelets. The properties of HNPs are described with particular focus on emergent synergetic characteristics. Of these, the light-induced charge-separation effect across the semiconductor-metal nanojunction is of particular interest as a basis for the utilization of HNPs in photocatalytic applications. The extensive studies on the charge-separation behavior and its dependence on the HNPs structural characteristics, environmental and chemical conditions, and light excitation regime are surveyed. Combining the advanced synthetic control with the charge-separation effect has led to demonstration of various applications of HNPs in different fields. A particular promise lies in their functionality as photocatalysts for a variety of uses, including solar-to-fuel conversion, as a new type of photoinitiator for photopolymerization and 3D printing, and in novel chemical and biomedical uses.

Epitaxial Orientation Angle Tuned Disk-on-Rod Nanoheterostructures for Boosting Charge Transfer

Controlling the compositions of Se(VI) and Te(VI) ions in a 2D disk on 1D structures of Sb(V) chalcogenides, disk-on-rod heterostructures having three different epitaxial angles with different surface facets are reported. Te injection temperature determined the composition, ensuring heterostructure formation with trigonal Sb₂Se_xTe_3-x disks on orthorhombic Sb₂Se₃ rods having orientation angles 180°, 135°, and 90°. The growth kinetics of disks connected at one/two heads of parent rods is manipulated using an Se precursor as a limiting reagent. Theoretical calculations established the energy minimization of different orientations, their possible formation, and suitability in energy transfer applications. Electrochemical measurements were also in agreement with theoretical calculations. Hence, this is a case study of advanced modular synthesis of disk-on-rod nanostructures, leading a step further in nanocrystal engineering for more desirable complex structures and their charge transfer property.