Currently, the most efficient organic light emitting devices (OLEDs) are based on dye-doped OLEDs. The major obstacle has been developing a host material for blue OLEDs that has sufficiently high energy of emission (\u3c380nm) to facilitate energy transfer to the dye. Previous studies of bis(diphenylphosphino)-E-Stilbene (P-STIL) suggested that tertiary aromatic diphosphines (TAPs) may be suitable candidates. Therefore, the P-containing materials, 4,4\u27-bis(naphthylphenylphosphino)biphenyl (alpha-P-NPD) and 4,4\u27-bis(diphenylphosphino)biphenyl (P-DDB) were synthesized and the photophysical properties were evaluated and compared to P-STIL. The TAPs were shown to be sensitive to air oxidation both in solution and the solid state and that the origin of the high energy emission of P-STIL was from the oxide. Furthermore, all TAPs were shown to exhibit dual emission, which may result from different structural geometries about the P-atom in the excited state. Theses studies conclusively demonstrate that TAPs are not suitable as host materials fro blue dye-doped OLEDs, but the fully oxidized materials, which are more stable and emit at higher energy may be better candidates
