Indium-tin oxide treatments for single- and double-layer polymeric light-emitting diodes: The relation between the anode physical, chemical, and morphological properties and the device performance

J. S. Kim, M. Granström, R. H. Friend, N. Johansson, W. R. Salaneck, Rusli Daik, W. J. Feast, F. Cacialli

Research output: Contribution to journalArticle

626 Citations (Scopus)

Abstract

We report combined studies of the influence of chemical and physical treatments on the properties of indium-tin oxide (ITO) thin films. The ITO films were also used as transparent anodes of polymeric light-emitting diodes (LEDs) incorporating poly(p-phenylene vinylene) (PPV) as the emitter material, with, or without, doped poly(3,4-ethylene dioxythiophene) (PEDOT) as a hole-injection/transport layer. Structures based on a soluble green derivative of PPV, poly(4,4′-diphenylene diphenylvinylene) were also tested. We studied chemical (aquaregia, degreasing, RCA protocol) and physical (oxygen and argon plasmas, Teflon, and paper rubbing) treatments and, in contrast to recently published work, we find that for Balzer Baltracon ITO, oxygen plasma and not aquaregia yields the highest efficiencies and luminances and the lowest drive voltages. For oxygen-plasma-treated anodes, the device efficiency clearly correlates with the value of the ITO surface work function, which in turn depends on the time of treatment. Interestingly, we find that work-function variations induced by our oxygen-plasma treatment are unchanged after long-term storage in air and in the dark. Unexpectedly, we also find that devices incorporating a PEDOT layer benefit from an appropriate treatment of the ITO surface, for both efficiency and lifetime. The results shed light on the physics of conjugated, organic semiconductors and related devices, and in particular on the presence and the role of an anodic energy barrier on the LEDs mechanism of operation. We also discuss the implications of our integrated experimental study in relation to the modification of the ITO sheet resistance, surface and bulk composition, and surface morphology

Original languageEnglish
Pages (from-to)6859-6870
Number of pages12
JournalJournal of Applied Physics
Volume84
Issue number12
Publication statusPublished - 15 Dec 1998
Externally publishedYes

Fingerprint

chemical properties
indium oxides
tin oxides
anodes
light emitting diodes
physical properties
oxygen plasma
ethylene
teflon (trademark)
argon plasma
organic semiconductors
luminance
oxide films
emitters
injection
life (durability)
physics
air
electric potential
thin films

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physics and Astronomy (miscellaneous)

Cite this

Indium-tin oxide treatments for single- and double-layer polymeric light-emitting diodes : The relation between the anode physical, chemical, and morphological properties and the device performance. / Kim, J. S.; Granström, M.; Friend, R. H.; Johansson, N.; Salaneck, W. R.; Daik, Rusli; Feast, W. J.; Cacialli, F.

In: Journal of Applied Physics, Vol. 84, No. 12, 15.12.1998, p. 6859-6870.

Research output: Contribution to journalArticle

@article{ce211c25993d4427886419766c23a6be,
title = "Indium-tin oxide treatments for single- and double-layer polymeric light-emitting diodes: The relation between the anode physical, chemical, and morphological properties and the device performance",
abstract = "We report combined studies of the influence of chemical and physical treatments on the properties of indium-tin oxide (ITO) thin films. The ITO films were also used as transparent anodes of polymeric light-emitting diodes (LEDs) incorporating poly(p-phenylene vinylene) (PPV) as the emitter material, with, or without, doped poly(3,4-ethylene dioxythiophene) (PEDOT) as a hole-injection/transport layer. Structures based on a soluble green derivative of PPV, poly(4,4′-diphenylene diphenylvinylene) were also tested. We studied chemical (aquaregia, degreasing, RCA protocol) and physical (oxygen and argon plasmas, Teflon, and paper rubbing) treatments and, in contrast to recently published work, we find that for Balzer Baltracon ITO, oxygen plasma and not aquaregia yields the highest efficiencies and luminances and the lowest drive voltages. For oxygen-plasma-treated anodes, the device efficiency clearly correlates with the value of the ITO surface work function, which in turn depends on the time of treatment. Interestingly, we find that work-function variations induced by our oxygen-plasma treatment are unchanged after long-term storage in air and in the dark. Unexpectedly, we also find that devices incorporating a PEDOT layer benefit from an appropriate treatment of the ITO surface, for both efficiency and lifetime. The results shed light on the physics of conjugated, organic semiconductors and related devices, and in particular on the presence and the role of an anodic energy barrier on the LEDs mechanism of operation. We also discuss the implications of our integrated experimental study in relation to the modification of the ITO sheet resistance, surface and bulk composition, and surface morphology",
author = "Kim, {J. S.} and M. Granstr{\"o}m and Friend, {R. H.} and N. Johansson and Salaneck, {W. R.} and Rusli Daik and Feast, {W. J.} and F. Cacialli",
year = "1998",
month = "12",
day = "15",
language = "English",
volume = "84",
pages = "6859--6870",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "12",

}

TY - JOUR

T1 - Indium-tin oxide treatments for single- and double-layer polymeric light-emitting diodes

T2 - The relation between the anode physical, chemical, and morphological properties and the device performance

AU - Kim, J. S.

AU - Granström, M.

AU - Friend, R. H.

AU - Johansson, N.

AU - Salaneck, W. R.

AU - Daik, Rusli

AU - Feast, W. J.

AU - Cacialli, F.

PY - 1998/12/15

Y1 - 1998/12/15

N2 - We report combined studies of the influence of chemical and physical treatments on the properties of indium-tin oxide (ITO) thin films. The ITO films were also used as transparent anodes of polymeric light-emitting diodes (LEDs) incorporating poly(p-phenylene vinylene) (PPV) as the emitter material, with, or without, doped poly(3,4-ethylene dioxythiophene) (PEDOT) as a hole-injection/transport layer. Structures based on a soluble green derivative of PPV, poly(4,4′-diphenylene diphenylvinylene) were also tested. We studied chemical (aquaregia, degreasing, RCA protocol) and physical (oxygen and argon plasmas, Teflon, and paper rubbing) treatments and, in contrast to recently published work, we find that for Balzer Baltracon ITO, oxygen plasma and not aquaregia yields the highest efficiencies and luminances and the lowest drive voltages. For oxygen-plasma-treated anodes, the device efficiency clearly correlates with the value of the ITO surface work function, which in turn depends on the time of treatment. Interestingly, we find that work-function variations induced by our oxygen-plasma treatment are unchanged after long-term storage in air and in the dark. Unexpectedly, we also find that devices incorporating a PEDOT layer benefit from an appropriate treatment of the ITO surface, for both efficiency and lifetime. The results shed light on the physics of conjugated, organic semiconductors and related devices, and in particular on the presence and the role of an anodic energy barrier on the LEDs mechanism of operation. We also discuss the implications of our integrated experimental study in relation to the modification of the ITO sheet resistance, surface and bulk composition, and surface morphology

AB - We report combined studies of the influence of chemical and physical treatments on the properties of indium-tin oxide (ITO) thin films. The ITO films were also used as transparent anodes of polymeric light-emitting diodes (LEDs) incorporating poly(p-phenylene vinylene) (PPV) as the emitter material, with, or without, doped poly(3,4-ethylene dioxythiophene) (PEDOT) as a hole-injection/transport layer. Structures based on a soluble green derivative of PPV, poly(4,4′-diphenylene diphenylvinylene) were also tested. We studied chemical (aquaregia, degreasing, RCA protocol) and physical (oxygen and argon plasmas, Teflon, and paper rubbing) treatments and, in contrast to recently published work, we find that for Balzer Baltracon ITO, oxygen plasma and not aquaregia yields the highest efficiencies and luminances and the lowest drive voltages. For oxygen-plasma-treated anodes, the device efficiency clearly correlates with the value of the ITO surface work function, which in turn depends on the time of treatment. Interestingly, we find that work-function variations induced by our oxygen-plasma treatment are unchanged after long-term storage in air and in the dark. Unexpectedly, we also find that devices incorporating a PEDOT layer benefit from an appropriate treatment of the ITO surface, for both efficiency and lifetime. The results shed light on the physics of conjugated, organic semiconductors and related devices, and in particular on the presence and the role of an anodic energy barrier on the LEDs mechanism of operation. We also discuss the implications of our integrated experimental study in relation to the modification of the ITO sheet resistance, surface and bulk composition, and surface morphology

UR - http://www.scopus.com/inward/record.url?scp=0032534440&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032534440&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0032534440

VL - 84

SP - 6859

EP - 6870

JO - Journal of Applied Physics

JF - Journal of Applied Physics

SN - 0021-8979

IS - 12

ER -