Tetrathiafulvalenes, oligoacenenes, and their buckminsterfullerene derivatives: the brick and mortar of organic electronics.

Optical properties of small inorganic and organic metal particles

The past several years have witnessed vigorous activity and dramatic progress in the area of low-dimensional electrically conductive materials.1 Great excitement has been generated among chemists and physicists by the synthesis and properties of unusual new substances with metal-like properties. These developments can be anticipated to lead to new degrees of chemical control over collective solid state properties, new methodology in chemical synthesis and in physical measurements, and to better theoretical models for cooperative phenomena in condensed matter. In the technological sphere, this research may lead to a new generation of electronic materials with applications as varied as sensors, rectifiers, fuel cell components, solar energy conversion elements, and electrophotographic devices. The possibility of high-temperature superconductors or at least highly conductive synthetic materials which could replace metals in various applications, has contributed additional impetus to the design and study of new metal-like materials.

Highly Conductive Halogenated Low-Dimensional Materials

Low temperature metallic conductivity in bis(tetrathiotetracene) triiodide, a new organic metal

The solid state physical properties of an isomorphous series of TTF salts (TTF11 (SCN)6, TTF11 (SeCN)6, and TTF7I5) were examined. While there was no noticeable trend in the conductivity (as a function of temperature and anion), the effective Fermi energy (?F) and the magnetic susceptibility transition temperature exhibited a definite trend as a function of anion. There is a correlation between the above properties and subtle variations in solid state structure of each of the above salts.

A systematic study of an isomorphous series of organic solid state conductors based on tetrathiafulvalene

The electrical resistivity and thermoelectric power of the organic semiconductor tetrathiotetracene (TTT) and its chloride, bromide, iodide, and thiocyanate salts are reported as a function of temperature. The ion–radical salts, of nearly 1:1 stoichiometry, were discovered to be highly conducting organic semiconductors and have resistivity values at room temperature ranging from 2.3 × 103 Ω·cm for TTT–chloride to 0.71 Ω·cm for TTT–iodide. The sign of the Seebeck coefficient of TTT–chloride corresponds to an n‐type semiconductor, while for TTT and the other salts it indicates p‐type behavior. Infrared absorption spectra of the solids, uv–visible spectra of solutions, preliminary x‐ray powder patterns and density measurements are correlated with electrical properties. The influence of constitution of the ion–radical salts on the electrical resistivity and possible mechanisms of conduction are discussed.

E. A. Perez‐Albuerne

Papers

Highly Conducting Ion‐Radical Salts of Tetrathiotetracene