Blue electroluminescent devices based on a trimeric phenylenvinylene derivative as emitting layer

We demonstrated blue organic light-emitting devices employing a novel blue-light-material, 2,5,2′,5′-tetrakis (4′-fluorostyryl) biphenyl as emitting layer. Maximum brightness and luminous efficiency were of 1828 cd/m2 at 9 V drive voltage and of 1.92 cd/A at 16 V. Commission Internationale de 1'Eclairage (CIE) coordinates are x = 0.20 and y = 0.22. The device color purity was further improved by introducing 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline as hole-blocking layer. Here, CIE coordinates are x = 0.16 and y = 0.20. A maximum brightness 1834 cd/m2 was achieved at 17 V. The peak current efficiencies was 1.52 cd/A at 10 V.