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

L. S.C. Pingree; M. T. Russell; T. J. Marks; M. C. Hersam

doi:10.1016/j.tsf.2006.11.186

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

L. S.C. Pingree, M. T. Russell, T. J. Marks, M. C. Hersam^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

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 language	English (US)
Pages (from-to)	4783-4787
Number of pages	5
Journal	Thin Solid Films
Volume	515
Issue number	11
DOIs	https://doi.org/10.1016/j.tsf.2006.11.186
State	Published - Apr 9 2007

Funding

This work was supported by the NASA Institute for Nanoelectronics and Computing under Award Number NCC 2–1363 and the National Science Foundation under Award Number DMR-0134706. The authors also acknowledge the use of facilities supported by the Northwestern University MRSEC (NSF DMR-0076097). Finally, the authors thank Jianfeng Li for synthesizing the TPD-Si 2 .

Keywords

Indium tin oxide
Negative capacitance
Optoelectronic devices
Surface and interface states

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Surfaces and Interfaces
Surfaces, Coatings and Films
Metals and Alloys
Materials Chemistry

Access to Document

10.1016/j.tsf.2006.11.186

Cite this

@article{f84401d7473b4e42993d4e4dd4b50e23,

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, {T. J.} and Hersam, {M. C.}",

note = "Funding Information: This work was supported by the NASA Institute for Nanoelectronics and Computing under Award Number NCC 2–1363 and the National Science Foundation under Award Number DMR-0134706. The authors also acknowledge the use of facilities supported by the Northwestern University MRSEC (NSF DMR-0076097). Finally, the authors thank Jianfeng Li for synthesizing the TPD-Si 2 .",

year = "2007",

month = apr,

day = "9",

doi = "10.1016/j.tsf.2006.11.186",

language = "English (US)",

volume = "515",

pages = "4783--4787",

journal = "Thin Solid Films",

issn = "0040-6090",

publisher = "Elsevier B.V.",

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, T. J.

AU - Hersam, M. C.

N1 - Funding Information: This work was supported by the NASA Institute for Nanoelectronics and Computing under Award Number NCC 2–1363 and the National Science Foundation under Award Number DMR-0134706. The authors also acknowledge the use of facilities supported by the Northwestern University MRSEC (NSF DMR-0076097). Finally, the authors thank Jianfeng Li for synthesizing the TPD-Si 2 .

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

AN - SCOPUS:33847158883

SN - 0040-6090

VL - 515

SP - 4783

EP - 4787

JO - Thin Solid Films

JF - Thin Solid Films

IS - 11

ER -

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

Abstract

Funding

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this