Two-layer light-emitting diodes based on sexithiophene and derivatives

The performance of oligothiophene‐based organic LEDs can be dramatically improved (by up to four orders of magnitude) by using a two‐layer device made of unsubstituted sexithiophene (6T) and a substituted 6T (see Fig.), although the substituted 6T materials do not produce electroluminescence in single‐layer devices. Yellow emission with a quantum yield of 0.15% has been achieved.