Rational Tuning of Metal–Semiconductor Nano-Icosapods for Plasmon-Induced Photodetection

Abstract

Plasmonic metal–semiconductor heterostructures with well-defined morphologies and spatial architectures have emerged as promising materials for wide applications in photocatalysis and optoelectronics. However, the synthesis of such structures with high quality and high yield remains a great challenge due to the incompatibility between the two materials. Herein, we report an optimized approach for the controlled preparation of branched Ag-CdS icosapods, which possess 20 CdS arms with an ordered spatial arrangement on the Ag cores. Moreover, the length, diameter, and thickness of the CdS arms on the Ag nanoparticles can be precisely tuned by the synthetic conditions, leading to Ag-CdS icosapods with tunable absorption properties. Furthermore, more complex hierarchical nanostructures can be achieved by the secondary growth of nanoplate arrays on the CdS arms. As a proof of concept, a phototransistor based on the self-assembled monolayer film of Ag-CdS icosapods shows a stable photoresponse and quite a fast switching performance under optical illumination of 540 nm without excitation of the CdS, which originates from the generation and transfer of plasmon-induced hot carriers in the Ag-CdS icosapods under an applied bias. This work offers a reproducible approach to finely tuning metal–semiconductor heterostructures with desirable architectures and paves the way for more deeply understanding their structure–property correlation.

Oriented Linear Self-Assembly of Colloidal Nanocrystals through Regioselective Formation of Hydrogen-Bonded Supramolecular Bridges

“…For instance, by controlling the relative proportions of nanorods and nanodumbbells (Figure e) or nanoplates and nanodumbbells (Figure f), specific chain structures reminiscent of block copolymers can be observed. Given the recent advances in precisely controlling the morphology and exposed facets of colloidal NCs, − we anticipate the design of chain-like superstructures with even more complex architectures and functionalities in the future, by taking advantage of the high facet specificity inherent in this PEG-mediated assembly process.…”

Halide Ions Regulating the Morphologies of PbS and Au@PbS Core–Shell Nanocrystals: Synthesis, Self-Assembly, and Electrical Transport Properties

“…The corresponding EDS elemental mapping shows that the metal cores are distributed in the interior of the PbS shells. Note that trioctylphosphine is added to prevent the possible sulfidization of the Ag NPs during the synthesis of Ag@PbS core–shell NCs. , …”

One-Pot Growth of Dual-Semiconductor Coshells on Au Nanorods with Tunable Band Arrangements for Efficient Photocatalysis

“…In a typical metal–semiconductor core–shell hybrids, the metal cores usually are Au, Ag, or Cu nanocrystals. − Various kinds of semiconductor shells have been grown on the metal cores, such as metal oxides (TiO 2 , ZnO, Cu 2 O, CeO 2 ), − binary chalcogenides (CdS, PbS, CdSe), − and ternary chalcogenides (AuAgS, AgZnSnS, CuInS 2 ). , Although the meta@semiconductor core–shell hybrids have been proven to show higher photocatalytic performance than bare semiconductors, the final photoactivity still has room for improvement. Semiconductor heterojunctions, in which two different semiconductors are integrated together, are widely studied in photocatalytic energy conversion. − The combination of semiconductors with different bandgaps can not only greatly extend the light response range but also form a built-in electric field to enhance charge separation of the photogenerated carriers, further improving the photocatalytic efficiency. , Z-scheme, straddling-gap (type I), and staggered-gap junctions (type II) are the most studied semiconductor heterojunctions. − The combination of semiconductor junctions with metal cores can further improve the photocatalytic activity owing to plasmonic absorption and plasmon-mediated charge transfer.…”