Bipolar behavior revealed by D-π-D chromophores bearing dithienothiophene (DTT) as π-center in redox- and LE properties

A series of D/D- and D/A pair conjugated chromophores based on dithienothiophene, DTT, as conjugated linker (π-center) were synthesized (D-π-D and D-π-A) and studied optical and electrochemical properties. Unusual bipolar behavior was observed with D-π-D, displaying the redox property similar to that of D-π-A. Single-layer light-emitting (LE) devices fabricated with such electronically dissimilar oligomers exhibited a close resemblance in their diode characteristics that are commonly observed with bipolar LE materials.