Monitoring interface traps in operating organic light-emitting diodes using impedance spectroscopy

L. S C Pingree, M. T. Russell, Tobin J Marks, Mark C Hersam

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Electronic trap densities at the indium tin oxide (ITO)/hole transport layer (HTL) interface in operating organic light-emitting diodes (OLEDs) are characterized in situ using impedance spectroscopy. For OLEDs with a high density of active trap states, negative values of the frequency derivative of resistance are clearly observable for frequencies on the order of 10 kHz, whereas positive values are observed when the trap density is low With this technique, it is revealed that the trap density is minimized via the introduction of a TPD-Si2 (4,4′-bis[(p-trichlorosilylpropylphenyl) phenylamino]-biphenyl) passivation layer at the ITO/HTL interface or by the application of large electric fields during device operation. Furthermore, impedance spectroscopy illustrates that the ITO/HTL interface is not a simple series resistance when traps are present since they are shown not to contribute to high frequency conduction. Overall, this paper demonstrates that the parasitic effects of interface traps can mask the underlying negative capacitive transport in OLEDs and presents a technique capable of monitoring the trap density of buried interfaces in organic electronic devices.

Original languageEnglish
Pages (from-to)4783-4787
Number of pages5
JournalThin Solid Films
Volume515
Issue number11
DOIs
Publication statusPublished - Apr 9 2007

Fingerprint

Organic light emitting diodes (OLED)
Tin oxides
Indium
light emitting diodes
traps
Spectroscopy
impedance
Monitoring
spectroscopy
indium oxides
tin oxides
Temperature programmed desorption
Passivation
Masks
Electric fields
Derivatives
indium tin oxide
electronics
passivity
masks

Keywords

  • Indium tin oxide
  • Negative capacitance
  • Optoelectronic devices
  • Surface and interface states

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Surfaces and Interfaces

Cite this

Monitoring interface traps in operating organic light-emitting diodes using impedance spectroscopy. / Pingree, L. S C; Russell, M. T.; Marks, Tobin J; Hersam, Mark C.

In: Thin Solid Films, Vol. 515, No. 11, 09.04.2007, p. 4783-4787.

Research output: Contribution to journalArticle

@article{5bfe4f32253d4b5491f2a5f2ae4391f5,
title = "Monitoring interface traps in operating organic light-emitting diodes using impedance spectroscopy",
abstract = "Electronic trap densities at the indium tin oxide (ITO)/hole transport layer (HTL) interface in operating organic light-emitting diodes (OLEDs) are characterized in situ using impedance spectroscopy. For OLEDs with a high density of active trap states, negative values of the frequency derivative of resistance are clearly observable for frequencies on the order of 10 kHz, whereas positive values are observed when the trap density is low With this technique, it is revealed that the trap density is minimized via the introduction of a TPD-Si2 (4,4′-bis[(p-trichlorosilylpropylphenyl) phenylamino]-biphenyl) passivation layer at the ITO/HTL interface or by the application of large electric fields during device operation. Furthermore, impedance spectroscopy illustrates that the ITO/HTL interface is not a simple series resistance when traps are present since they are shown not to contribute to high frequency conduction. Overall, this paper demonstrates that the parasitic effects of interface traps can mask the underlying negative capacitive transport in OLEDs and presents a technique capable of monitoring the trap density of buried interfaces in organic electronic devices.",
keywords = "Indium tin oxide, Negative capacitance, Optoelectronic devices, Surface and interface states",
author = "Pingree, {L. S C} and Russell, {M. T.} and Marks, {Tobin J} and Hersam, {Mark C}",
year = "2007",
month = "4",
day = "9",
doi = "10.1016/j.tsf.2006.11.186",
language = "English",
volume = "515",
pages = "4783--4787",
journal = "Thin Solid Films",
issn = "0040-6090",
publisher = "Elsevier",
number = "11",

}

TY - JOUR

T1 - Monitoring interface traps in operating organic light-emitting diodes using impedance spectroscopy

AU - Pingree, L. S C

AU - Russell, M. T.

AU - Marks, Tobin J

AU - Hersam, Mark C

PY - 2007/4/9

Y1 - 2007/4/9

N2 - Electronic trap densities at the indium tin oxide (ITO)/hole transport layer (HTL) interface in operating organic light-emitting diodes (OLEDs) are characterized in situ using impedance spectroscopy. For OLEDs with a high density of active trap states, negative values of the frequency derivative of resistance are clearly observable for frequencies on the order of 10 kHz, whereas positive values are observed when the trap density is low With this technique, it is revealed that the trap density is minimized via the introduction of a TPD-Si2 (4,4′-bis[(p-trichlorosilylpropylphenyl) phenylamino]-biphenyl) passivation layer at the ITO/HTL interface or by the application of large electric fields during device operation. Furthermore, impedance spectroscopy illustrates that the ITO/HTL interface is not a simple series resistance when traps are present since they are shown not to contribute to high frequency conduction. Overall, this paper demonstrates that the parasitic effects of interface traps can mask the underlying negative capacitive transport in OLEDs and presents a technique capable of monitoring the trap density of buried interfaces in organic electronic devices.

AB - Electronic trap densities at the indium tin oxide (ITO)/hole transport layer (HTL) interface in operating organic light-emitting diodes (OLEDs) are characterized in situ using impedance spectroscopy. For OLEDs with a high density of active trap states, negative values of the frequency derivative of resistance are clearly observable for frequencies on the order of 10 kHz, whereas positive values are observed when the trap density is low With this technique, it is revealed that the trap density is minimized via the introduction of a TPD-Si2 (4,4′-bis[(p-trichlorosilylpropylphenyl) phenylamino]-biphenyl) passivation layer at the ITO/HTL interface or by the application of large electric fields during device operation. Furthermore, impedance spectroscopy illustrates that the ITO/HTL interface is not a simple series resistance when traps are present since they are shown not to contribute to high frequency conduction. Overall, this paper demonstrates that the parasitic effects of interface traps can mask the underlying negative capacitive transport in OLEDs and presents a technique capable of monitoring the trap density of buried interfaces in organic electronic devices.

KW - Indium tin oxide

KW - Negative capacitance

KW - Optoelectronic devices

KW - Surface and interface states

UR - http://www.scopus.com/inward/record.url?scp=33847158883&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33847158883&partnerID=8YFLogxK

U2 - 10.1016/j.tsf.2006.11.186

DO - 10.1016/j.tsf.2006.11.186

M3 - Article

VL - 515

SP - 4783

EP - 4787

JO - Thin Solid Films

JF - Thin Solid Films

SN - 0040-6090

IS - 11

ER -