A novel emitter for organic light emitting diodes

Organic light emitting diodes (OLEDs) have been regarded as the display technology for future generation. In this study, π-conjugated of benzochromene and pyranochromenone derivatives (BS01-BS08) were synthesized for applying in OLEDs using the Sonogashira cross-coupling reaction and the ruthenium cyclization reaction, respectively. The compounds were characterized by 1H and 13C NMR, FTIR and mass spectroscopy. In the ruthenium cyclization step, two isomer products were generated from asymmetric diphenylacetylene. The major products were 11-14% yields clearly characterized by 13C NMR. Their photoluminescence emission at room temperature appeared in the green region of the fluorescence process. All synthesized compounds which were in the ITO/NPB/BS01-BS08/Bphen/LiF/Al structure were used as dopants for OLEDs. It was found that BS02 showed the best performance and exhibited green colour. Its current efficiency was 1.28 cd/A and its power efficiency was 0.47 Im/W.