Self‐Assembly of Functional Molecules into 1D Crystalline Nanostructures

Self‐assembled functional nanoarchitectures are employed as important nanoscale building blocks for advanced materials and smart miniature devices to fulfill the increasing needs of high materials usage efficiency, low energy consumption, and high‐performance devices. One‐dimensional (1D) crystalline nanostructures, especially molecule‐composed crystalline nanostructures, attract significant attention due to their fascinating infusion structure and functionality which enables the easy tailoring of organic molecules with excellent carrier mobility and crystal stability. In this review, we discuss the recent progress of 1D crystalline self‐assembled nanostructures of functional molecules, which include both a small molecule‐derived and a polymer‐based crystalline nanostructure. The basic principles of the molecular structure design and the process engineering of 1D crystalline nanostructures are also discussed. The molecular building blocks, self‐assembly structures, and their applications in optical, electrical, and photoelectrical devices are overviewed and we give a brief outlook on crucial issues that need to be addressed in future research endeavors.     

Self‐Organized Nanostructures in Hard Ceramic Coatings

Nanostructures have attracted increasing interest in modern development of hard coatings for wear‐resistant applications. In plasma‐assisted vapor deposited thin films, nanostructures can evolve during growth or a post‐deposition annealing treatment. In this review we demonstrate, using TiB_2.4, TiN–TiB₂, Ti_0.34Al_0.66N, and Ti(N,B) as model‐coatings, the development of nanostructures and its influence on the mechanical properties of ceramic thin films. For TiB_2.4 and TiN–TiB₂ a two‐dimensional and three‐dimensional nanostructure, respectively, organizes itself during growth by segregation driven processes. Growth of Ti_0.34Al_0.66N and Ti(N,B) results in the formation of a supersaturated TiN based phase, which tends to decompose into its stable constituents during post‐deposition annealing via the formation of nm‐sized domains. As the hardness of a material is determined by resistance to bond distortion and dislocation formation and motion, which depend on the amount and constitution of obstacles provided, there is a direct relation between hardness and nanostructure.     

Self‐Assembled Photonic Structures

Photonic crystals have proven their potential and are nowadays a familiar concept. They have been approached from many scientific and technological flanks. Among the many techniques devised to implement this technology self‐assembly has always been one of great popularity surely due to its ease of access and the richness of results offered. Self‐assembly is also probably the approach entailing more materials aspects owing to the fact that they lend themselves to be fabricated by a great many, very different methods on a vast variety of materials and to multiple purposes. To these well‐known material systems a new sibling has been born (photonic glass) expanding the paradigm of optical materials inspired by solid state physics crystal concept. It is expected that they may become an important player in the near future not only because they complement the properties of photonic crystals but because they entice the researchers’ curiosity. In this review a panorama is presented of the state of the art in this field with the view to serve a broad community concerned with materials aspects of photonic structures and more so those interested in self‐assembly.