Spectral studies of white organic light-emitting devices based on multi-emitting layers

Abstract White organic light emitting devices (WOLEDs) with an RBG stacked multilayer structure were demonstrated. In RGB stacked OLEDs, blue emitting, 2-t-butyl-9,10-di-(2-naphthyl)anthracene (TBADN) doped with p-bis(p-N,N-diphenyl-amono-styryl)benzene (DSA-Ph), green emitting, tris-(8-hydroxyquinoline)aluminum (Alq) doped with C545, and red emitting, tris-[8-hydroxyquinoline]aluminum (Alq) doped with 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)- 4H-pyran (DCJTB), were used. By adjusting the order and thickness of emitting layer in RBG structure, we got a white OLED with current efficiency of 5.60 cd/A and Commission Internationale De L’Eclairage (CIE) coordinates of (0.34, 0.34) at 200 mA/cm2. Its maximum luminance was 20,700 cd/m2 at current density of 400 mA/cm2. The results have been explained on the basis of the theory of excitons generation and diffusion. According to the theory of excitons generation and diffusion, an equation has been set up which relates EL spectra to the thickness of every layer and to the exciton diffusion length.

[1]  Wenqing Zhu,et al.  Study of blue organic light emitting diode by inserting a red dye ultra thin layer at the emitting layer , 2005 .

[2]  Gang Cheng,et al.  White organic light-emitting devices , 2004 .

[3]  Fumio Sato,et al.  High-efficiency white phosphorescent organic light-emitting devices with greenish-blue and red-emitting layers , 2003 .

[4]  Joseph Shinar,et al.  Bright small molecular white organic light-emitting devices with two emission zones , 2002 .

[5]  Michael C. Petty,et al.  Pure RGB Emissions Based on a White OLED Combined with Optical Colour Filters , 2006 .

[6]  Yasuo Tomita,et al.  Highly-bright white organic light-emitting diodes based on a single emission layer , 2002 .

[7]  Yu-Tai Tao,et al.  Bright white organic light-emitting diode , 2001 .

[8]  Zhaoxin Wu,et al.  Investigation of the spectra of phosphorescent organic light-emitting devices in relation to emission zone , 2005 .

[9]  Feng Li,et al.  Thickness dependent emission color of organic white light-emitting devices , 2003 .

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

[11]  Dashan Qin,et al.  White organic light-emitting diode comprising of blue fluorescence and red phosphorescence , 2005 .

[12]  C. H. Chen,et al.  Electroluminescence of doped organic thin films , 1989 .

[13]  Yong Qiu,et al.  Bright white organic light-emitting diodes based on two blue emitters with similar molecular structures , 2005 .

[14]  Joseph Shinar,et al.  Bright white small molecular organic light-emitting devices based on a red-emitting guest–host layer and blue-emitting 4,4′-bis(2,2′-diphenylvinyl)-1,1′-biphenyl , 2002 .

[15]  Byung-Jun Jung,et al.  ORGANIC WHITE LIGHT EMITTING DEVICES WITH AN RGB STACKED MULTILAYER STRUCTURE , 2003 .

[16]  Feng Li,et al.  White-electrophosphorescence devices based on rhenium complexes , 2003 .