A series of new carbazole derivatives with good solubility and electronic properties for use as host materials for blue phosphorescent organic light-emitting diodes is reported. A twisted biphenyl moiety at the center of the host materials was applied to enhance the solubility as well as triplet energies. Hence all the molecules showed good solubility as well as a fairly large triplet energy up to 3.01 eV. Blue phosphorescent devices employing bis (4, 6- ...
