Introduction of Organic Superconducting Materials

Since the first discovery of an organic superconductor in 1980, TMTSF₂PF₆ (TMTSF = tetramethyltetraselenafulvalene) with the superconducting (SC) transition temperature (T _c) = 0.9 K under 12 kbar, over 140 organic superconductors have been found. Among them, the highest T _c of the two-dimensional (2D) sulfur-based organic superconductors is 14.2 K under 82 kbar for β’-(BEDT-TTF)₂ICl₂ (BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) and 3D C₆₀-based superconductor is 38K for Cs₃C₆₀ under 7 kbar. In this chapter, the development, crystal growth, and the characteristic features of pseudo-1D, 2D, and 3D molecular superconductors are introduced.