Magnetic moment assisted layer-by-layer film formation of a Prussian Blue analog

Innovation in Layer-by-Layer Assembly

Methods for depositing thin films are important in generating functional materials for diverse applications in a wide variety of fields. Over the last half-century, the layer-by-layer assembly of nanoscale films has received intense and growing interest. This has been fueled by innovation in the available materials and assembly technologies, as well as the film-characterization techniques. In this Review, we explore, discuss, and detail innovation in layer-by-layer assembly in terms of past and present developments, and we highlight how these might guide future advances. A particular focus is on conventional and early developments that have only recently regained interest in the layer-by-layer assembly field. We then review unconventional assemblies and approaches that have been gaining popularity, which include inorganic/organic hybrid materials, cells and tissues, and the use of stereocomplexation, patterning, and dip-pen lithography, to name a few. A relatively recent development is the use of layer-by-layer assembly materials and techniques to assemble films in a single continuous step. We name this "quasi"-layer-by-layer assembly and discuss the impacts and innovations surrounding this approach. Finally, the application of characterization methods to monitor and evaluate layer-by-layer assembly is discussed, as innovation in this area is often overlooked but is essential for development of the field. While we intend for this Review to be easily accessible and act as a guide to researchers new to layer-by-layer assembly, we also believe it will provide insight to current researchers in the field and help guide future developments and innovation.

Molecular rectifiers based on donor/acceptor assemblies: effect of orientation of the components' magnetic moments

In forming donor/acceptor assemblies that act as molecular rectifiers, we have introduced magnetic organic molecules as electron-donating and electron-accepting moieties. We have oriented the magnetic moment of the donor and acceptor components separately and immobilized them (and their moments) so that the molecular assemblies that act as rectifiers could be formed with moments mutually parallel or anti-parallel to each other. We have characterized the molecular assemblies formed on an electrode with a scanning tunneling microscope tip. Such donor/acceptor assemblies with a control over the orientation of moments of the components provided unique systems to study the effect of the nature of alignment on molecular rectifiers. We have observed that the rectification ratio increased in junctions with moments of the components being parallel to each other. The improvement in the rectification ratio has been explained in terms of an efficient electron-transfer process in a moment-aligned junction between the donor and acceptor moieties.