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

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.

Automated summary

Composite inorganic nanoarchitectures, fabricated through wet-chemical synthetic techniques, offer advanced functionalities due to the coexistence and synergistic interactions among different materials. The design and synthesis of these structures have been extensively studied, leading to the development of new nanomaterials with unique properties and wide-ranging applications.