White organic light-emitting devices with a bipolar transport layer between blue fluorescent and yellow phosphor-sensitized-fluorescent emitting layers

Abstract We report white organic light-emitting devices (WOLEDs) based on 4,4′-bis(2,2′-diphenylvinyl)-1,1′-biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12-tetraphenylnaphthacene (rubrene). By introducing a bipolar transport 4,4′-N,N′-dicarbazole-biphenyl (CBP) layer between the fluorescent and the phosphor-sensitized-fluorescent layers, additional light emission from the phosphorescence sensitized layer is observed. This can be attributed to the elimination of the Dexter energy transfer between these two emitters. White emission with Commission International de L’Eclairage coordinates of (0.22,0.33) and a maximum luminance of 22,360 cd/m 2 were obtained. The maximum current efficiency can reach 10.7 cd/A.

[1]  S. R. Forrest,et al.  High-efficiency fluorescent organic light-emitting devices using a phosphorescent sensitizer , 2000, Nature.

[2]  Stephen R. Forrest,et al.  Management of singlet and triplet excitons for efficient white organic light-emitting devices , 2006, Nature.

[3]  Lewis J. Rothberg,et al.  Color variation with electroluminescent organic semiconductors in multimode resonant cavities , 1994 .

[4]  S. Forrest,et al.  Nearly 100% internal phosphorescence efficiency in an organic light emitting device , 2001 .

[5]  Feng Li,et al.  White organic light-emitting devices using a phosphorescent sensitizer , 2003 .

[6]  Stephen R. Forrest,et al.  Efficient Organic Electrophosphorescent White‐Light‐Emitting Device with a Triple Doped Emissive Layer , 2004 .

[7]  C. Shu,et al.  Highly efficient white-electrophosphorescent devices based on polyfluorene copolymers containing charge-transporting pendent units , 2007 .

[8]  Stephen R. Forrest,et al.  White Organic Light‐Emitting Devices for Solid‐State Lighting , 2004 .

[9]  Stephen R. Forrest,et al.  White Light Emission Using Triplet Excimers in Electrophosphorescent Organic Light‐Emitting Devices , 2002 .

[10]  Shiyong Liu,et al.  White light emission from exciplex using tris-(8-hydroxyquinoline)aluminum as chromaticity-tuning layer , 2001 .

[11]  Heume-Il Baek,et al.  Simple white organic light emitting diodes with improved color stability and efficiency using phosphorescent and fluorescent emitters , 2008 .

[12]  Gregor Schwartz,et al.  Highly efficient white organic light emitting diodes comprising an interlayer to separate fluorescent and phosphorescent regions , 2006 .

[13]  Modeeparampil N. Kamalasanan,et al.  White organic LEDs and their recent advancements , 2006 .