A novel approach for merging two or more materials to form hybrid materials with artificially tunable properties has been presented in a study published in the journal ACS Applied Nano Materials.
Hybrid Materials – Two Materials are Better Than One
Owing to immense diversity in the choice of materials and considerable promise in electrical and optical equipment, novel hybrid nanomaterials have piqued the curiosity of many researchers.
These hybrid nanomaterials are developed through the merging of different nanomaterials. This allows the newly developed materials to possess artificially tailored physical characteristics and various functionalities.
The architecture and evolution of hybrid nanomaterials play a critical role in the characteristics of materials in various applications, demanding precise processing procedures and methodologies.
To develop hybrid nanomaterials, there are two methodologies: top-down procedures, including patterning and lithography, and bottom-up techniques, such as self-assembled growth.
The Rise of VANs
Vertically aligned nanocomposites (VANs), which fall into the category of bottom-up procedures, have efficiently integrated two epitaxial stages in a vertical grown columnar manner on diverse substrates.
The VAN architecture is known for its excellent plasmonic and optical feature tuning, strong ferro-electromagnetic properties, and high ion transfer capabilities. These, along with nanoscale characteristics, epitaxial sheet quality, and extremely anisotropic physical characteristics, allow VANs to outperform other hybrid nanomaterial designs.
Two-Phase VAN Networks
The majority of prior VAN investigations have focused on oxide-oxide two-phase networks, in which one phase has significant physical qualities while the second oxide phase exhibits high vertical strain pairing across surfaces.
Oxide-metal VAN devices have emerged as a promising class of VAN systems. These devices utilize the ability of VAN to merge multiple extremely dissimilar phases—that is, oxides and metals, to attain remarkable optical characteristics such as reconfigurable hyperbolic optical reactions, improved nonlinearities, and epsilon-near-zero (ENZ) wavelength.
Owing to its unique characteristics and adjustability, this novel class of VANs opens up new possibilities in plasmonics and optical designing.
Factors Affecting VAN Systems
Prior research has shown that the deposition frequency may effectively modify the diameter of the nanopillar in the BiFeO3-Sm2O3 VAN systems, thus influencing the general physical parameters.
In ZnO-Au VAN-based thin sheets, the partial pressure of oxygen efficiently controls the growth, altering the thin sheet morphology from hexagon-shaped nanopillars to unevenly shaped and positioned nanopillars.
Another factor pertinent to the effective two-phase dispersion is the strain within the substrate. It can be observed that the majority of adjustments in VAN have been proven in two-phase VAN systems, with very little research on three-phase VAN systems.
Cobalt Alloy-Based Nanocomposites
In the past decade, considerable research has been carried out on Cobalt (Co) Alloy-based composites. It has been thoroughly demonstrated that Co and Co-alloy nanocomposites exhibit highly intriguing magnetic and optical characteristics, with the characteristics depending primarily on the size of the nanostructure.
In BaZrO3-Co, BTO-Co, CeO2-Co, and Zr2O-Co systems, Co was shown to grow effectively, producing nanocomposites with extremely desirable magnetic and optical characteristics.
Co is a less expensive alternative to the more popular plasmonic materials used in SPR sensing devices. The partial pressure of oxygen may readily control the fundamental architecture of any Co-based three-phase system.
To add to the advantages of Cobalt, thin-sheet composites with Co elements as tiny as 3 nm have been created using CeO2-Co composite sheets.
Optimizing VAN Morphology
In this paper, the team showed how to use unique three-phase composite architectures to ensure optimal VAN morphology adjustment.
The team used a complicated metal oxide-oxide structure, Co-CeO2-BaTiO3. Co was chosen for its strong ferromagnetic characteristics, as well as its distinctive plasmonic capabilities and surface plasmon resonance (SPR) phenomenon.
Key Findings of the Study
Using growth variable control, a unique three-phase metal-oxide-oxide VAN-based hybrid system of Co-CeO2-BTO with customizable sheet shape and physical characteristics was developed.
These self-assembled 3D nanostructures, such as nano-mushrooms grown using oxygen partial pressure and vacuum-grown nanopillars, provide new opportunities for thin-sheet materials to explore functionality tuning.
The team observed that the nano-mushroom architecture exhibited more fascinating optical features toward the lower end of the light spectrum owing to its hyperbolic behavior and SPR effect.
The team highlighted that complicated composite design offers great promise regarding microstructure adjustment in hybrid material architectures. These adjustments improve sensing devices' characteristics and various other systems such as dielectrics and optical waveguides.
Rutherford, B., Zhang, B. et al. (2022). Tunable Three-Phase Co-CeO2-BaTiO3 Hybrid Metamaterials with Nano-Mushroom-Like Structure for Tailorable Multifunctionalities. ACS Applied Nano Materials. Available at: https://pubs.acs.org/doi/10.1021/acsanm.2c00394