Functionalized terfluorene for solution-processed high efficiency blue fluorescence OLED and electrophosphorescent devices

A new multifunctional blue-emitting terfluorene derivative ( TFDPA ) featured with triphenylamine groups for hole-transportation and long alkyl chains for solution processability on the conjugation inert bridge centers was reported. TFDPA can give homogeneous thin film by solution process and exhibits high hole mobility ( μ h ≈ 10 −3 cm 2 V −1 s −1 ) and suitable HOMO for hole injection. Particularly, TFDPA performs efficient deep-blue emission with high quantum yield (∼100% in solution, 43% in thin film) and suitable triplet energy ( E T = 2.28 eV), making solution-processed OLED devices of using TFDPA as blue emitter and as host for iridium-containing phosphorescent dopants feasible. The solution-processed nondoped blue OLED device gives saturated deep-blue electroluminescence [CIE = (0.17, 0.07)] with EQE of 2.7%. TFDPA -hosted electrophosphorescent devices performed with EQE of 6.5% for yellow [(Bt) 2 Ir(acac)], 9.3% of orange [Ir(2–phq) 3 ], and 6.9% of red [(Mpq) 2 Ir(acac)], respectively. In addition, with careful control on the doping concentration of [(Bt) 2 Ir(acac)], a solution-processed fluorescence–phosphorescence hybrided two-color-based WOLED with EQE of 3.6% and CIE coordinate of (0.38, 0.33) was successfully achieved.