Exfoliated nanoplatelets of an Aurivillius phase, Bi3.25La0.75Ti3O12: Characterisation by X-ray diffraction and by high-resolution electron microscopy

Enhanced Photocatalytic Properties of Restacked Unilamellar [SrTa2O7]2- Nanosheets of Aurivillius Phase Layered Perovskites

In the present work, unilamellar [SrTa₂O₇]^2- perovskite nanosheets with variable lateral dimensions were synthesized via a high-yield, three-step liquid exfoliation route from layered Bi₂SrTa₂O₉. The photocatalytic activity of the parent and exfoliated layered perovskites was evaluated for the photocatalytic dye degradation of Rhodamine B under UV light (254 nm) and reduction of water to H₂ under the full solar spectrum. A comparative study of the photocatalytic behavior of unilamellar [SrTa₂O₇]^2- perovskite nanosheets and parent layered structure showed a significant improvement in both hydrogen evolution (98.20 vs 3 μmol g^-1) and Rhodamine B degradation time (180 vs 30 min), with the restacked nanosheets. The exfoliation of layered perovskites not only increases their specific surface area, providing more active sites, but also reduces the recombination probability of electrons and holes due to their unilamellar structure and reduced charge transport pathways. The synthesis and preparation of strong acid solids such as [SrTa₂O₇]^2- perovskite nanosheets can be a promising approach for effective adsorption of pollutants with cationic nature and more efficient electron transfer between the dye and catalyst. Finally, the photocatalytic characteristics of the restacked unilamellar [SrTa₂O₇]^2- nanosheets remained unchanged after three successive cycles of recycling-reusing.

Layer-by-layer assembly of versatile nanoarchitectures with diverse dimensionality: a new perspective for rational construction of multilayer assemblies

Over the past few decades, layer-by-layer (LbL) assembly of multilayer thin films has garnered considerable interest on account of its ability to modulate nanometer control over film thickness and its extensive choice of usable materials for coating planar and particulate substrates, thus allowing for the fabrication of responsive and functional thin films for their potential applications in a myriad of fields. Herein, we provide elaborate information on the current developments of LbL assembly techniques including different properties, molecular interactions, and assembly methods associated with this promising bottom-up strategy. In particular, we highlight the principle for rational design and fabrication of a large variety of multilayer thin film systems including multi-dimensional capsules or spatially hierarchical nanostructures based on the LbL assembly technique. Moreover, we discuss how to judiciously choose the building block pairs when exerting the LbL assembly buildup which enables the engineering of multilayer thin films with tailor-made physicochemical properties. Furthermore, versatile applications of the diverse LbL-assembled nanomaterials are itemized and elucidated in light of specific technological fields. Finally, we provide a brief perspective and potential future challenges of the LbL assembly technology. It is anticipated that our current review could provide a wealth of guided information on the LbL assembly technique and furnish firm grounds for rational design of LbL assembled multilayer assemblies toward tangible applications.

Two-dimensional dielectric nanosheets: novel nanoelectronics from nanocrystal building blocks

Two-dimensional (2D) nanosheets, which possess atomic or molecular thickness and infinite planar lengths, are regarded as the thinnest functional nanomaterials. The recent development of methods for manipulating graphene (carbon nanosheet) has provided new possibilities and applications for 2D systems; many amazing functionalities such as high electron mobility and quantum Hall effects have been discovered. However, graphene is a conductor, and electronic technology also requires insulators, which are essential for many devices such as memories, capacitors, and gate dielectrics. Along with graphene, inorganic nanosheets have thus increasingly attracted fundamental research interest because they have the potential to be used as dielectric alternatives in next-generation nanoelectronics. Here, we review the progress made in the properties of dielectric nanosheets, highlighting emerging functionalities in electronic applications. We also present a perspective on the advantages offered by this class of materials for future nanoelectronics.

Topochemical manipulation of perovskites: low-temperature reaction strategies for directing structure and properties

Topochemical reaction strategies offer an important low-temperature (<500 °C) approach to the conscious manipulation of various inorganic host materials, allowing access to compounds that cannot be prepared by standard high-temperature methods. As the utility of these strategies continues to expand, researchers will be able to more effectively target materials with technologically significant properties. This Progress Report presents recent advances in topochemical reaction strategies as applied to perovskite and perovskite-related compounds. Emphasis is placed on structural modifications and corresponding variations in properties. Additionally, the future prospects of this approach to the rational design of intricate target compounds are discussed.