Synthetic Approaches to Colloidal Nanocrystal Heterostructures Based on Metal and Metal-Oxide Materials

Abstract

Composite inorganic nanoarchitectures, based on combinations of distinct materials, represent advanced solid-state constructs, where coexistence and synergistic interactions among nonhomologous optical, magnetic, chemical, and catalytic properties lay a basis for the engineering of enhanced or even unconventional functionalities. Such systems thus hold relevance for both theoretical and applied nanotechnology-based research in diverse areas, spanning optics, electronics, energy management, (photo)catalysis, biomedicine, and environmental remediation. Wet-chemical colloidal synthetic techniques have now been refined to the point of allowing the fabrication of solution free-standing and easily processable multicomponent nanocrystals with sophisticated modular heterostructure, built upon a programmed spatial distribution of the crystal phase, composition, and anchored surface moieties. Such last-generation breeds of nanocrystals are thus composed of nanoscale domains of different materials, assembled controllably into core/shell or heteromer-type configurations through bonding epitaxial heterojunctions. This review offers a critical overview of achievements made in the design and synthetic elaboration of colloidal nanocrystal heterostructures based on diverse associations of transition metals (with emphasis on plasmonic metals) and transition-metal oxides. Synthetic strategies, all leveraging on the basic seed-mediated approach, are described and discussed with reference to the most credited mechanisms underpinning regioselective heteroepitaxial deposition. The unique properties and advanced applications allowed by such brand-new nanomaterials are also mentioned.

One-Pot Synthesis of Colloidal Hybrid Au (Ag)/ZnO Nanostructures with the Participation of Maleic Acid Copolymers

“…Based on the data obtained, it can be assumed that the heterostructures obtained are core-shell structures, where metal nanoparticles can be located in the core, and zinc oxide is located in the outer layer [ 3 ].…”

“…Lately, a focus has been on the conjugation of two or more nanomaterials to achieve increased multifunctionality as well as creating opportunities for the next generation materials (nanohybrids) with enhanced performance [ 1 , 2 ]. Among a variety of hybrid heterostructured materials, polyelement nanoparticles and metal-metal oxide heterostructures are widely studied and applied materials [ 2 , 3 , 4 ]. Great interest is caused by composites based on zinc oxide and metals—silver or gold.…”

Nickel Boride (NixB) Nanocrystals: From Solid-State Synthesis to Highly Colloidally Stable Inks

“…The exploration of nanoscaled materials has been extensive during the past decades for metals, − metal oxides, − and semiconductors. − The progress is demonstrated by the intense development of the synthetic methods for nanocrystals (NCs) , and their applications in catalysis, − optoelectronics, , and biomedicine. − …”

Hard–Soft Core–Shell Architecture Formation from Cubic Cobalt Ferrite Nanoparticles

“…Seed-mediated synthesis approaches consist of introducing pre-formed nanoparticles (seeds) into the medium containing the precursors of the shell material. The nucleation of the secondary material onto the surface of the seeds (heterogeneous nucleation) has a lower energy barrier than the formation of new particles of the secondary material (homogeneous nucleation), thus giving rise to the formation of the core–shell structures [ 62 ].…”