C 2 H 5 C 2 H 5 N N CH 3 CH 3 CH 3 CH 3 CH 3 N C 2 H 5 C 2 H 5 N N CH 3 CH 3 CH 3 CH 3 CH 3 N C 2 H 5 C 2 H 5 N N CH 3 CH 3 CH 3 CH 3 CH 3 N C 2 H 5 C 2 H 5 N N CH 3 CH 3 CH 3 CH 3 CH 3 N CH 3 CH 3 CH 3 CH 3 CH 3 N A. Fischer, S. Forget, S. Chénais , M.-C. Castex, Lab. de Physique des Lasers, Univ. Paris Nord, France Highly efficient multilayer organic Highly efficient multilayer organic pure-blue-light emitting diodes with pure-blue-light emitting diodes with substituted carbazole compounds in the substituted carbazole compounds in the emitting layer. emitting layer. D. Adès, A. Siove, Lab. Biomateriaux et Polymères de Spécialité, Univ. Paris Nord, France C. Denis, P. Maisse and B. Geffroy Lab. Cellules et Composants, CEA Saclay, France
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A. Fischer, S. Forget, S. Chénais, M.-C. Castex, Lab. de Physique des Lasers, Univ. Paris Nord, France Highly efficient multilayer organic pure-blue- light.
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C2H5
C2H5
N
N
CH3 CH3
CH3 CH3
CH3
N
C2H5
C2H5
N
N
CH3 CH3
CH3 CH3
CH3
N
C2H5
C2H5
N
N
CH3 CH3
CH3 CH3
CH3
N C2H5
C2H5
N
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CH3 CH3
CH3 CH3
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A. Fischer, S. Forget, S. Chénais, M.-C. Castex,Lab. de Physique des Lasers, Univ. Paris Nord, France
Highly efficient multilayer organic pure-Highly efficient multilayer organic pure-blue-light emitting diodes with blue-light emitting diodes with
substituted carbazole compounds in the substituted carbazole compounds in the emitting layer.emitting layer.
Highly efficient multilayer organic pure-Highly efficient multilayer organic pure-blue-light emitting diodes with blue-light emitting diodes with
substituted carbazole compounds in the substituted carbazole compounds in the emitting layer.emitting layer.
D. Adès, A. Siove, Lab. Biomateriaux et Polymères de Spécialité, Univ. Paris Nord, France
C. Denis, P. Maisse and B. GeffroyLab. Cellules et Composants, CEA Saclay, France
2CLEO ’06 – Long Beach (USA)
Outline
Introduction : why BLUE oleds ? Two new carbazolic compounds : PMC (Pentamethylcarbazole) and DEC (Dimer of N-ethylcarbazole)
Devices using neat films of PMC and DEC in single layer and multilayer structures Devices using doped films of PMC:DPVBi and DEC:DPVBi Conclusion
Ultrathin light sources, lightweightHigh brightness and viewing angle > 160°Low drive voltage (3-10 V) and low power consumptionExtremely rich diversity of materials : All visible colors available (≠ inorganic LEDs), including saturated colorsPotentially flexible Long lifetimes (> 20 000 h reported)Low cost potential for mass production
%• High operating voltage (20 V), crystallization during operation (short-circuit)
DEC
ITO
Al
h
VD. Romero, A. Siove et al., Adv. Mater. 9, 1158
(1997)
This work : Use of DEC (and PMC) in a multilayer OLED structure with both neat films and doped films configurations: efficient deep-blue organic emitter
Bad performance due to recombination and quenching of excitons at Al/DEC interface, poor charge injection
We demonstrated state-of-the-art external quantum efficiency of 3.3% with a deep-blue OLED (CIE x = 0.15 ; y = 0.17) using a DEC:DPVBi emitting mixture
Close to the max 5% = 25% (singlet/triplet ratio) x 20% (extraction
efficiency)
Efficiency of the doping approach : DEC:DPVBi better than DPVBi alone (or DPVBI:PMC) : attributed to enhanced trapping of charged carriers
PMC exhibits the most saturated color (x = 0.15 ; y= 0.10) : better efficiency would be achievable with a different design while keeping the CIE coordinates (in progress)