A phosphine oxide-substituted double spirobifluorene compound with high thermal stability

Abstract

A high thermal stability spirobifluorene core derivative with a substituted diphenylphosphine oxide moiety was synthesized as a new electron transport material (spiro(cyclopenta[def]fluorene-1,5,9 9-bifluorene)-2 ,2diylbis(diphenylphosphineoxide) [DSPPO1]) for phosphorescent organic light-emitting diodes (PHOLEDs). The glass transition temperature of DSPPO1 was observed at 156°C and was higher than that of common electron transport materials. The triplet energy of DSPPO1 was 2.77 eV and DSPPO1 was appropriate as an electron transport material for PHOLEDs. The highest occupied molecular orbital and lowest unoccupied molecular orbital of DSPPO1 were − 6.51 and − 2.70 eV, respectively. The energy level of DSPPO1 was suitable for hole blocking and electron injection as an electron transport material for PHOLEDs.

P‐175: High Triplet Energy Exciplex Forming Hole Type Host for High Performance in Deep‐blue Phosphorescent Organic Light‐emitting Diodes

“…Therefore, the efficiency or operation lifetime of the device can be determined depending on the properties of host materials. [1][2][3][4]7,8] In recent years, a lot of materials were mixed to induce exciplex formation and it was used as a host of phosphorescent organic lightemitting diodes (PhOLEDs). [5,6] Unlike unipolar host system, exciplex host system uses hole type material and electron type material which have a large energy level difference to make the driving voltage lower, improve EQE, and increase operation lifetime.…”