Synthesis of new N-heteroaromatic attached tetraphenylethene based luminogens having aggregation induced emission and their applications in organic light emitting diodes

Aggregation induced emission is an auxiliary property that can eliminate the aggregation caused quenching effect. It is a common undesired emission characteristic of most bulky aromatic molecules. Tetraphenylethene, with its unique features, is the most commonly studied molecule having aggregation induced emission property. In this work four N heteroaromatic attached tetraphenylethene derivatives were synthesized via inexpensive C-N bond formation reactions. The synthesized luminogens showed good thermal properties, having high Td values between 366 degrees C and 505 degrees C. All four tetraphenylethene derivatives exhibited excellent aggregation induced emission properties and there was an up to 200-fold increase in their fluorescence intensities. According to the time-resolved emission decay experimental analyses, all four luminogens showed two relaxation pathways in a THE - water mixture (10-90%). Non doped turquoise and light green OLED devices using the synthesized luminogens as a light emitting layer exhibited a maximum brightness up to 2600 cd/m(2), a maximum current efficiency up to 3.6 cd/A, turn on voltages between 7.0 and 10.0 V, and external quantum efficiencies up to 1.5%. (C) 2016 Elsevier B.V. All rights reserved.