Over the last ten years, conjugated oligothiophenes have emerged as one of
the largest families of organic semiconductors with potential applications
in electronics devices. Thin film transistors (TFTs), photovoltaic solar ce
lls, light-emitting diodes (LEDs), light modulators, photochromic switches
and laser microcavities are some examples of devices that have been fabrica
ted with oligothiophenes as the active materials. The key advantage of well
-defined oligomers over their parent polymers is the high degree of molecul
ar and crystalline ordering they can achieve. Polycrystalline and highly or
iented thin films can be easily prepared from solution or by vacuum deposit
ion. In many cases it has even been possible to grow single crystals and el
ucidate their X-ray structure. The aim of this review is to describe the st
ructure of oligothiophene crystals and thin films and to explore its implic
ations on the performances of various electronic devices.