High-brightness white light-emitting organic electroluminescent devices using poly(N-vinylcarbazole) as a hole-transporter

A white light-emitting organic electroluminescent (EL) device with multilayer thin-film structure, which shows high-brightness and high-efficiency, is demonstrated. The device structure of glass substrate/indium–tin oxide/poly(N-vinylcarbazole) (PVK)/1,1,4,4-tetraphenyl-1,3-butadiene/8-(quinolinolate)-aluminum (Alq) doped with 5,6,11,12-tetraphenylnaphthacene/Alq/Mg/Al was employed. The turn-on voltage is as low as 2.5 V. The white light emission covers a wide range of the visible region, and the Commission Internationale de 1' Eclairage coordinates of the emitted light are (0.319, 0.332) at 10 V. Bright white light, over 20 000 cd/m2, was successfully obtained at about 18 V, and the maximum efficiency reaches to 1.24 lm/W at 9 V. The reasons of obtaining high level EL properties of our device have been discussed.

[1]  Ullrich Scherf,et al.  Highly efficient electroluminescence of new wide band gap ladder‐type poly(para‐phenylenes) , 1996 .

[2]  Alan J. Heeger,et al.  Laser emission from solutions and films containing semiconducting polymer and titanium dioxide nanocrystals , 1996 .

[3]  Mats Andersson,et al.  Semiconducting Polymers: A New Class of Solid-State Laser Materials , 1996, Science.

[4]  S. Chen,et al.  White-light emission from electroluminescence diode with polyaniline as the emitting layer , 1996 .

[5]  Ananth Dodabalapur,et al.  White organic electroluminescence devices , 1996 .

[6]  Daoben Zhu,et al.  Light-emitting diodes based on an alternating copolymer containing triphenylamine and phenylene units , 1999 .

[7]  Stephen R. Forrest,et al.  Relationship between electroluminescence and current transport in organic heterojunction light‐emitting devices , 1996 .

[8]  Shiyong Liu,et al.  Effect of well number on organic multiple-quantum-well electroluminescent device characteristics , 1998 .

[9]  Ullrich Scherf,et al.  Efficient white light-emitting diodes realized with new processable blends of conjugated polymers , 1997 .

[10]  A. Heeger,et al.  Electroluminescence from blend films of poly(3-hexylthiophene) and poly(N-vinylcarbazole) , 1995 .

[11]  Göran Gustafsson,et al.  White light from an electroluminescent diode made from poly[3(4‐octylphenyl)‐2,2′‐bithiophene] and an oxadiazole derivative , 1994 .

[12]  Paras N. Prasad,et al.  SOLID-STATE TUNABLE CAVITY LASING IN A POLY(PARA-PHENYLENE VINYLENE) DERIVATIVE ALTERNATING BLOCK CO-POLYMER , 1997 .

[13]  Tetsuo Tsutsui,et al.  Confinement of charge carriers and molecular excitons within 5‐nm‐thick emitter layer in organic electroluminescent devices with a double heterostructure , 1990 .

[14]  Jingsong Huang,et al.  White light emission induced by confinement in organic multiheterostructures , 1999 .

[15]  Prasad,et al.  Observation of photorefractivity in a fullerene-doped polymer composite. , 1992, Physical review. B, Condensed matter.

[16]  William R. Salaneck,et al.  Calcium electrodes in polymer LEDs , 1995 .

[17]  R. H. Partridge,et al.  Electroluminescence from polyvinylcarbazole films: 1. Carbazole cations , 1983 .

[18]  R. N. Marks,et al.  Light-emitting diodes based on conjugated polymers , 1990, Nature.

[19]  C. Tang,et al.  Organic Electroluminescent Diodes , 1987 .

[20]  L. Xiao-dong,et al.  Influence of the Energy Level Matching on the Performances of Organic/Polymeric Electroluminescent Devices , 1996 .

[21]  Martin Pfeiffer,et al.  LOW VOLTAGE ORGANIC LIGHT EMITTING DIODES FEATURING DOPED PHTHALOCYANINE AS HOLE TRANSPORT MATERIAL , 1998 .

[22]  Yoshio Taniguchi,et al.  DOPED ORGANIC LIGHT EMITTING DIODES HAVING A 650-NM-THICK HOLE TRANSPORT LAYER , 1998 .

[23]  Katsutoshi Nagai,et al.  Multilayer White Light-Emitting Organic Electroluminescent Device , 1995, Science.

[24]  C. Lee.  Enhanced efficiency and durability of organic electroluminescent devices by inserting a thin insulating layer at the Alq3/cathode interface , 1997 .

[25]  S. Chen,et al.  White light emission from exciplex in a bilayer device with two blue light-emitting polymers , 1998 .

[26]  Yang Yang,et al.  Efficient blue-green and white light-emitting electrochemical cells based on poly[9,9-bis(3,6-dioxaheptyl)-fluorene-2,7-diyl] , 1997 .

[27]  Olle Inganäs,et al.  White light emission from a polymer blend light emitting diode , 1996 .