A quantitative numerical model of multilayer vapor-deposited organic light emitting diodes

A one-dimensional numerical model for the quantitative simulation of multilayer organic light emitting diodes (OLEDs) is presented. It encompasses bipolar charge carrier drift with field-dependent mobilities and space charge effects, charge carrier diffusion, trapping, bulk and interface recombination, singlet exciton diffusion and quenching effects. Using field-dependent mobility data measured on unipolar single layer devices, reported energetic levels of highest occupied and lowest unoccupied molecular orbitals, and realistic assumptions for experimentally not direct accessible parameters, current density and luminance of state-of-the-art undoped vapor-deposited two- and three-layer OLEDs with maximum luminance exceeding 10000 cd/m2 were successfully simulated over 4 orders of magnitude. For an adequate description of these multilayer OLEDs with energetic barriers at interfaces between two adjacent organic layers, the model also includes a simple theory of charge carrier barrier crossing and recombinati...

[1]  K. C. Kao,et al.  Electrical Transport in Solids , 1983 .

[2]  I. Campbell,et al.  Device model investigation of single layer organic light emitting diodes , 1998 .

[3]  Marie Angelopoulos,et al.  Materials and modeling for organic light-emitting diodes , 1997, Photonics West.

[4]  Donal D. C. Bradley,et al.  Angular Dependence of the Emission from a Conjugated Polymer Light‐Emitting Diode: Implications for efficiency calculations , 1994 .

[5]  S R Forrest,et al.  High-external-quantum-efficiency organic light-emitting devices. , 1997, Optics letters.

[6]  N. Peyghambarian,et al.  Photoemission spectroscopy of LiF coated Al and Pt electrodes , 1998 .

[7]  H. Bässler,et al.  Charge carrier recombination in organic bilayer electroluminescent diodes. II. Experiment , 1997 .

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

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

[10]  J. B. Birks,et al.  Photophysics of aromatic molecules , 1970 .

[11]  H. Bässler,et al.  Langevin‐Type Charge Carrier Recombination in a Disordered Hopping System , 1995 .

[12]  A. Heeger,et al.  Visible light emission from semiconducting polymer diodes , 1991 .

[13]  Paul Davids,et al.  Device model for single carrier organic diodes , 1997 .

[14]  Yongli Gao,et al.  Trap states of tris-8-(hydroxyquinoline) aluminum and naphthyl-substituted benzidine derivative using thermally stimulated luminescence , 1998 .

[15]  D. Pai,et al.  Comparison of the drift mobility measured under transient and steady-state conditions in a prototypical hopping system , 1986 .

[16]  C. Tang,et al.  Enhanced electron injection in organic electroluminescence devices using an Al/LiF electrode , 1997 .

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

[18]  Damodar M. Pai,et al.  Hole transport in solid solutions of a diamine in polycarbonate , 1984 .

[19]  Junliang Yang,et al.  Doping effects in organic electroluminescent devices , 1998 .

[20]  Shiyong Liu,et al.  Measurement of electron/hole mobility in organic/polymeric thin films using modified time-of-flight apparatus , 1997 .

[21]  Xueyin Jiang,et al.  Stability enhancement of organic electroluminescent diode through buffer layer or rubrene doping in hole-transporting layer , 1997 .

[22]  H. Bässler,et al.  Charge carrier recombination in organic bilayer electroluminescent diodes. I. Theory , 1997 .

[23]  Stephen R. Forrest,et al.  Organic films deposited on Si p‐n junctions: Accurate measurements of fluorescence internal efficiency, and application to luminescent antireflection coatings , 1996 .

[24]  Jie Yang,et al.  Physical mechanisms in double-carrier trap-charge limited transport processes in organic electroluminescent devices: A numerical study , 1998 .

[25]  W. Stampor,et al.  Electric field effect on luminescence efficiency in 8-hydroxyquinoline aluminum (Alq3) thin films , 1997 .

[26]  K. Obata,et al.  Fluorescence Lifetime of Organic Thin Films Alternately Deposited with Diamine Derivative and Aluminum Quinoline , 1997 .

[27]  H. Bässler,et al.  A model of electroluminescence in organic double‐layer light‐emitting diodes , 1996 .

[28]  Donal D. C. Bradley,et al.  Space-charge limited conduction with traps in poly(phenylene vinylene) light emitting diodes , 1997 .

[29]  H. Bässler,et al.  Models of organic light-emitting diodes , 1997 .

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

[31]  Ian D. Parker,et al.  Carrier tunneling and device characteristics in polymer light‐emitting diodes , 1994 .

[32]  Vladimir Arkhipov,et al.  Charge injection into light-emitting diodes: Theory and experiment , 1998 .

[33]  Hiroshi Inada,et al.  Multilayered organic electroluminescent device using a novel starburst molecule, 4,4’,4‘‐tris(3‐methylphenylphenylamino)triphenylamine, as a hole transport material , 1994 .

[34]  H. Bässler.  Charge Transport in Disordered Organic Photoconductors a Monte Carlo Simulation Study , 1993 .

[35]  Donal D. C. Bradley,et al.  Space-charge-limited charge injection from indium tin oxide into a starburst amine and its implications for organic light-emitting diodes , 1998 .

[36]  M. Lampert,et al.  Current injection in solids , 1970 .