Carbazolyl benzo[1,2-b:4,5-b']difuran: an ambipolar host material for full-color organic light-emitting diodes

We have designed an ambipolar material, 3,7-bis[4-(N-carbazolyl)-phenyl]-2,6-diphenylbenzo[1,2-b:4,5-b']difuran (CZBDF), and synthesized it by zinc-mediated double cyclization. Its physical properties clarified that CZBDF possesses a wide-gap character, well-balanced and high hole and electron mobilities of larger than 10(-3) cm(2) V(-1) s(-1), and a high thermal stability. Using CZBDF as a host material for heterojunction OLED devices, a full range of visible emission was obtained. Notably, CZBDF also enabled us to fabricate RGB-emitting homojunction OLEDs, with performances comparable or superior to the heterojunction devices composed of several materials.