Highly Efficient Red Phosphorescent Osmium(II) Complexes for OLED Applications

Abstract

The nonionic, red-emitting complexes [Os(fppz)2L2] (L = PPh2Me (1), PPhMe2 (2)) and [Os(bptz)2L2] (L = PPh2Me (3)) were synthesized, showing highly intense red phosphorescent emission in CH2Cl2 solution at λmax 617, 632, and 649 nm, respectively. The electroluminescent properties of these compounds on OLEDs showed promising device efficiencies required for future OLED applications.

Recent Progresses on Materials for Electrophosphorescent Organic Light‐Emitting Devices

“…[153][154][155] For example, the enhanced steric hindrance of molecules reduced the concentration quenching for red phosphorescence. The EQE was increased to 11.6% in the devices employing a highly sterically hindered red phosphorescent dye of (3-trifl uoromethyl-5-(2-pyridyl)-1,2,4-triazole) 2 Os (phosphine) 2 ((fptz) 2 Os(PPh 2 Me) 2 ) doped into the n -type host BAlq with a concentration of 15 wt.% as the emitting layer.…”

New heteroleptic cyclometalated iridium(III) complexes containing 2-(2′,4′-difluorophenyl)-4-methylpyridine for organic light-emitting diode applications

“…The mixing of singlet and triplet excited states by doping phosphorescent dyes into a charge-transporting host as emissive layers greatly enhances the internal phosphorescence quantum efficiency of OLEDs toward 100% [12][13][14]. Adequate modification of the coordinated ligands can tune the emission color from red/green to blue, although blue phosphorescent emitters are more difficult to achieve than red/ green [15][16][17].…”

Organic Semiconductor Electroluminescent Materials

“…The phosphorescence life time is 0.6-1.9 μs, and the EL emission peak is from 620 to 650 nm, with color coordinates around (0.65, 0.33). (fppz) 2 Os(PPhMe2) 2 [173], (fppz) 2 Os(PPh2Me) 2 [174], and (tptz) 2 Os 6 Organic Semiconductor Electroluminescent Materials(PPh2Me) 2 [175] are all charge neutral red phosphorescent emitters. When (fptz) 2 Os(PPh2Me) 2 was reported for the first time, NPB or 9,9-bis[4-(N,N-bis-biphenyl-4-yl-amino)phenyl]-9H-fluorene (BPAPF) were used as HTL and bathocuproine (BCP) was used as HBL.…”