White Light Emission Using Triplet Excimers in Electrophosphorescent Organic Light-Emitting Devices

Highly Efficient Red Phosphorescent OLEDs Based on Ir(III) Complexes with Fluorine-substituted Benzoylphenylpyridine Ligand

“…Fig. 2 shows the absorption and emission spectra of the Ir(III) complexes (1)(2)(3)(4), and their data is summarized in Table 1. The absorption spectra of Ir(III) complexes 1-4 below 360 nm were assigned to the spin-allowed 1 π-π * transition involving Bzppy (benzoylphenyl pyridine) ligands, and the band at approximately 400 nm to a spin-allowed metal charge transfer ( 1 MLCT) band.…”

“…[1][2][3] In addition, it is possible to increase their internal quantum efficiency to 100%, corresponding to an external quantum efficiency of > 20%. 4,5 These devices employ phosphorescent heavy metal complexes as the emitting materials that emit in the triplet metal-to-ligand charge transfer ( 3 MLCT) state.…”

Improving the Performance of Phosphorescent Based White Polymer Light Emitting Devices Using Iridium Complexes

“…Since pure PVK has poor electron-transporting properties, oxadiazole compound such as 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole(PBD) have often been added to PVK. In fact, many studies have shown that PVK:PBD blends with PBD concentrations in the range of 30-50% serve as good hosts for small molecule emitters and highly efficient polymer-based LEDs based on this system have been reported [12][13][14][15][16][17][18][19]. In this study, we report single layer white PLEDs with an emission layer containing a blend of two phosphorescent iridium complexes within a PVK-PBD host matrix.…”

“…To achieve white emission, mixtures of the three red, green and blue(RGB) primary colors or two complementary colors, are typically required. Various approaches towards realizing WOLEDs have been reported, including multilayer structures capable of sequential energy transfer, multiple component emissive layers containing an appropriate of RG phosphorescent or fluorescent dopants [11][12][13][14][15]. Polymer blends containing RGB emitting species, charge transfer exciplexes or excimers braoad emission and single component layers that utilize a polymer with broad emission [16][17][18][19][20][21][22].…”

White organic light emitting devices based on multiple emissive nanolayers

“…In order to generate the desired white light, WOLEDs with various configurations have been proposed [7][8][9][10][11][12][13], such as: (a) a multilayer device with blue, green, and red emission layers; (b) a doped device with a host material and blue, green, and red fluorescence dyes; (c) a single emission layer device with white emission materials; (d) excimer and exciplex emission; and (e) tandem structure [14][15][16][17][18][19][20][21][22][23]. Among these approaches, WOLEDs employing multi-emissive layer structure has advantages over other architectures in terms of efficiency and color controlability because the recombination current, singlet and triplet energy transfer and performance of each layer can be controlled by layer thickness, doping concentration and charge blocking layers.…”