ABSTRACT
As the physical limits of conventional silicon-based electronics are approached, the search for new types of materials that can deliver smaller devices grows up. Molecular electronics, which uses assemblies of individual molecules to reproduce conventional structures, such as switches or semiconductors, represents the new frontier. In this context, molecule-based materials, namely, materials built from predesigned molecular building blocks, play a key role since they are known to exhibit many technologically important properties (e.g., magnetic ordering, conductivity, superconductivity), traditionally considered to be solely available for classic atombased inorganic solids such as metals, alloys, or oxides. Their relevance in material science is mainly due to the tunability of their
physical properties by conventional synthetic methods; molecular materials in fact are obtained through soft routes, traditionally from organic chemistry, coordination chemistry, and supramolecular chemistry, and this opens unprecedented possibilities to the design of molecules with the desired size, shape, charge, polarity, and electronic properties, in response to the changing demands of technology. The area of molecular materials with interesting technological properties started almost 75 years ago with the †‹•…‘˜‡”›‘ˆ–Š‡ϐ‹”•–…‘’Ž‡š‡••Š‘™‹‰•’‹…”‘••‘˜‡”–”ƒ•‹–‹‘• [Fe(S2NCR2)3].1 Since then molecular materials have given rise to complexes with spin crossover transition2 semiconductors, metals and superconductors,3 ferrimagnets, ferromagnets and weak ferromagnets,4 chromophores,5 including those for nonlinear optics (NLO) and Visible-NIR (NearInfrared) emitters based on lanthanide complexes with polyconjugated ligands.6 Because of their versatility and peculiar optical, magnetic, and conducting properties, moleculebased materials are appealing candidates for practical applications in post-silicon molecular electronics and spintronics (a new paradigm of electronics based on the spin degree of freedom of the electron).7
