1，3，4-Oxadiazole/Spiro-9，9′-xanthene fluorene host materials and their red and green phosphorescent devices

1，3，4-oxadiazole/spiro-9，9′-xanthene-fluorene spirocyclic compound 2，5-bis（2（2-spiro‑9，9′‑xanthene-fluorene phenyl）-1，3，4-oxadiazole （D［2-SFXP］-o-OXD） was used as the host material， ［Ir（pq）₂acac］ and ［Ir（mppy）₃］ were used as the red and green phosphorescent guest material that were doped into the host material with doping concentration of 6% and 4% as the emitting layers to fabricate the red and green phosphorescent devices by solution-processing method， respectively. The device results showed that the host material could effectively transfer the energy to the red and green phosphorescent guest materials， respectively， and the maximum current efficiencies of the devices were up to 5.7 cd/A and 15.8 cd/A， respectively. However， the device efficiencies decreased rapidly as the increasing of the driving voltage due to the poor energy level matching between the host and guest. Therefore， the improvement of the device performance could be achieved for further step through optimizing of the host material and device structure. Then， the stable and high efficient organic electroluminescent devices could be prepared.