Effect of mixed hole transporting host on the mobility, Gaussian density of states and efficiencies of a heterojunction phosphorescent organic light emitting diode

N. A. Talik, K. L. Woon, Boon Kar Yap

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We present an in-depth study of the hole transport in poly(vinylcarbazole) PVK films blended with small molecule tris(4-carbazoyl-9-ylphenyl)amine (TcTa). Doping TcTa in PVK introduces shallow hole traps when the doping concentration is lower than 20 wt%. It becomes percolative at higher concentrations. The energetic disorder σ of the blended system reduces from ∼72 meV at 0 wt% TcTa to ∼41 meV at 50 wt% TcTa. A correlation between σ and the film morphologies suggests that the blending of TcTa molecules in the film does not only change the film homogeneity and roughness but also the energetic disorder. In addition to the mobility study, we fabricated a red phosphorescent organic light emitting diode with the same blending system. By doping merely 5 wt% of TcTa into PVK as mixed hole-transporting hosts, the efficiency of the deep red heterojunction phosphorescent organic light emitting diode increased from 2 cd A-1 to 4 cd A-1, suggesting that TcTa molecules assist in hole injection.

Original languageEnglish
Article number155103
JournalJournal of Physics D: Applied Physics
Volume49
Issue number15
DOIs
Publication statusPublished - 15 Mar 2016

Fingerprint

Organic light emitting diodes (OLED)
Heterojunctions
heterojunctions
light emitting diodes
Doping (additives)
Molecules
disorders
Hole traps
molecules
homogeneity
Amines
low concentrations
amines
roughness
Surface roughness
traps
injection

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Cite this

@article{f7cbdb55e8e7478a8ab3a7a3d11a651f,
title = "Effect of mixed hole transporting host on the mobility, Gaussian density of states and efficiencies of a heterojunction phosphorescent organic light emitting diode",
abstract = "We present an in-depth study of the hole transport in poly(vinylcarbazole) PVK films blended with small molecule tris(4-carbazoyl-9-ylphenyl)amine (TcTa). Doping TcTa in PVK introduces shallow hole traps when the doping concentration is lower than 20 wt{\%}. It becomes percolative at higher concentrations. The energetic disorder σ of the blended system reduces from ∼72 meV at 0 wt{\%} TcTa to ∼41 meV at 50 wt{\%} TcTa. A correlation between σ and the film morphologies suggests that the blending of TcTa molecules in the film does not only change the film homogeneity and roughness but also the energetic disorder. In addition to the mobility study, we fabricated a red phosphorescent organic light emitting diode with the same blending system. By doping merely 5 wt{\%} of TcTa into PVK as mixed hole-transporting hosts, the efficiency of the deep red heterojunction phosphorescent organic light emitting diode increased from 2 cd A-1 to 4 cd A-1, suggesting that TcTa molecules assist in hole injection.",
author = "Talik, {N. A.} and Woon, {K. L.} and Yap, {Boon Kar}",
year = "2016",
month = "3",
day = "15",
doi = "10.1088/0022-3727/49/15/155103",
language = "English",
volume = "49",
journal = "Journal Physics D: Applied Physics",
issn = "0022-3727",
publisher = "IOP Publishing Ltd.",
number = "15",

}

TY - JOUR

T1 - Effect of mixed hole transporting host on the mobility, Gaussian density of states and efficiencies of a heterojunction phosphorescent organic light emitting diode

AU - Talik, N. A.

AU - Woon, K. L.

AU - Yap, Boon Kar

PY - 2016/3/15

Y1 - 2016/3/15

N2 - We present an in-depth study of the hole transport in poly(vinylcarbazole) PVK films blended with small molecule tris(4-carbazoyl-9-ylphenyl)amine (TcTa). Doping TcTa in PVK introduces shallow hole traps when the doping concentration is lower than 20 wt%. It becomes percolative at higher concentrations. The energetic disorder σ of the blended system reduces from ∼72 meV at 0 wt% TcTa to ∼41 meV at 50 wt% TcTa. A correlation between σ and the film morphologies suggests that the blending of TcTa molecules in the film does not only change the film homogeneity and roughness but also the energetic disorder. In addition to the mobility study, we fabricated a red phosphorescent organic light emitting diode with the same blending system. By doping merely 5 wt% of TcTa into PVK as mixed hole-transporting hosts, the efficiency of the deep red heterojunction phosphorescent organic light emitting diode increased from 2 cd A-1 to 4 cd A-1, suggesting that TcTa molecules assist in hole injection.

AB - We present an in-depth study of the hole transport in poly(vinylcarbazole) PVK films blended with small molecule tris(4-carbazoyl-9-ylphenyl)amine (TcTa). Doping TcTa in PVK introduces shallow hole traps when the doping concentration is lower than 20 wt%. It becomes percolative at higher concentrations. The energetic disorder σ of the blended system reduces from ∼72 meV at 0 wt% TcTa to ∼41 meV at 50 wt% TcTa. A correlation between σ and the film morphologies suggests that the blending of TcTa molecules in the film does not only change the film homogeneity and roughness but also the energetic disorder. In addition to the mobility study, we fabricated a red phosphorescent organic light emitting diode with the same blending system. By doping merely 5 wt% of TcTa into PVK as mixed hole-transporting hosts, the efficiency of the deep red heterojunction phosphorescent organic light emitting diode increased from 2 cd A-1 to 4 cd A-1, suggesting that TcTa molecules assist in hole injection.

UR - http://www.scopus.com/inward/record.url?scp=84962245982&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84962245982&partnerID=8YFLogxK

U2 - 10.1088/0022-3727/49/15/155103

DO - 10.1088/0022-3727/49/15/155103

M3 - Article

VL - 49

JO - Journal Physics D: Applied Physics

JF - Journal Physics D: Applied Physics

SN - 0022-3727

IS - 15

M1 - 155103

ER -