Phosphonic acid modification of indium-tin oxide electrodes: Combined XPS/UPS/ contact angle studies

Sergio A. Paniagua, Peter J. Hotchkiss, Simon C. Jones, Seth R. Marder, Anoma Mudalige, F. Saneeha Marrikar, Jeanne E Pemberton, Neal R Armstrong

Research output: Contribution to journalArticle

156 Citations (Scopus)

Abstract

Indium-tin oxide (ITO) electrodes have been modified with both fluorinated alkyl and aryl phosphonic acids [n-hexylphosphonic acid (HPA) and n-octadecylphosphonic acid (ODPA); 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecaf-luorooctyl phosphonic acid (FHOPA), pentafluorobenzyl phosphonic acid (PFBPA), and tetrafluorobenzyl-1,4-diphosphonic acid (TFBdiPA)]. These are modifiers designed to control both wetting properties toward nonpolar molecular solids and to provide a wide range of tunability in effective surface work function. The molecular nature of surface attachment and changes in electronic and wetting properties were characterized by X-ray photoelectron spectroscopy (XPS), UV-photoelectron spectroscopy (UPS), photoelastic modulation infrared reflection-absorption spectroscopy (PM-IRRAS), and contact angle measurements using both water and hexadecane. Interface dipoles from the PA modifiers contribute to shifts in the low kinetic energy regions of UPS spectra (local vacuum level shifts, which translate into changes in effective surface work function). We show that for ITO surfaces modified with FHOPA, and to a lesser extent with PFBPA, the high work function obtained by oxygen plasma cleaning can be maintained after modification, while decreasing the polar component of surface energy. This approach to oxide surface modification is a strategy that may be beneficial for the modification of transparent conducting oxide surfaces in both organic light emitting diodes and in organic solar cells, where oxide/organic compatibility can affect device performance.

Original languageEnglish (US)
Pages (from-to)7809-7817
Number of pages9
JournalJournal of Physical Chemistry C
Volume112
Issue number21
DOIs
StatePublished - May 29 2008

Fingerprint

Photoelectron spectroscopy
Tin oxides
Ultraviolet spectroscopy
indium oxides
Indium
tin oxides
Contact angle
X ray photoelectron spectroscopy
photoelectron spectroscopy
Electrodes
acids
electrodes
Acids
Oxides
x rays
Wetting
Phosphorous Acids
wetting
oxides
Organic light emitting diodes (OLED)

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Paniagua, S. A., Hotchkiss, P. J., Jones, S. C., Marder, S. R., Mudalige, A., Marrikar, F. S., ... Armstrong, N. R. (2008). Phosphonic acid modification of indium-tin oxide electrodes: Combined XPS/UPS/ contact angle studies. Journal of Physical Chemistry C, 112(21), 7809-7817. https://doi.org/10.1021/jp710893k

Phosphonic acid modification of indium-tin oxide electrodes : Combined XPS/UPS/ contact angle studies. / Paniagua, Sergio A.; Hotchkiss, Peter J.; Jones, Simon C.; Marder, Seth R.; Mudalige, Anoma; Marrikar, F. Saneeha; Pemberton, Jeanne E; Armstrong, Neal R.

In: Journal of Physical Chemistry C, Vol. 112, No. 21, 29.05.2008, p. 7809-7817.

Research output: Contribution to journalArticle

Paniagua SA, Hotchkiss PJ, Jones SC, Marder SR, Mudalige A, Marrikar FS et al. Phosphonic acid modification of indium-tin oxide electrodes: Combined XPS/UPS/ contact angle studies. Journal of Physical Chemistry C. 2008 May 29;112(21):7809-7817. https://doi.org/10.1021/jp710893k
Paniagua, Sergio A. ; Hotchkiss, Peter J. ; Jones, Simon C. ; Marder, Seth R. ; Mudalige, Anoma ; Marrikar, F. Saneeha ; Pemberton, Jeanne E ; Armstrong, Neal R. / Phosphonic acid modification of indium-tin oxide electrodes : Combined XPS/UPS/ contact angle studies. In: Journal of Physical Chemistry C. 2008 ; Vol. 112, No. 21. pp. 7809-7817.
@article{8e965553acd346b8847ae414e3e351c2,
title = "Phosphonic acid modification of indium-tin oxide electrodes: Combined XPS/UPS/ contact angle studies",
abstract = "Indium-tin oxide (ITO) electrodes have been modified with both fluorinated alkyl and aryl phosphonic acids [n-hexylphosphonic acid (HPA) and n-octadecylphosphonic acid (ODPA); 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecaf-luorooctyl phosphonic acid (FHOPA), pentafluorobenzyl phosphonic acid (PFBPA), and tetrafluorobenzyl-1,4-diphosphonic acid (TFBdiPA)]. These are modifiers designed to control both wetting properties toward nonpolar molecular solids and to provide a wide range of tunability in effective surface work function. The molecular nature of surface attachment and changes in electronic and wetting properties were characterized by X-ray photoelectron spectroscopy (XPS), UV-photoelectron spectroscopy (UPS), photoelastic modulation infrared reflection-absorption spectroscopy (PM-IRRAS), and contact angle measurements using both water and hexadecane. Interface dipoles from the PA modifiers contribute to shifts in the low kinetic energy regions of UPS spectra (local vacuum level shifts, which translate into changes in effective surface work function). We show that for ITO surfaces modified with FHOPA, and to a lesser extent with PFBPA, the high work function obtained by oxygen plasma cleaning can be maintained after modification, while decreasing the polar component of surface energy. This approach to oxide surface modification is a strategy that may be beneficial for the modification of transparent conducting oxide surfaces in both organic light emitting diodes and in organic solar cells, where oxide/organic compatibility can affect device performance.",
author = "Paniagua, {Sergio A.} and Hotchkiss, {Peter J.} and Jones, {Simon C.} and Marder, {Seth R.} and Anoma Mudalige and Marrikar, {F. Saneeha} and Pemberton, {Jeanne E} and Armstrong, {Neal R}",
year = "2008",
month = "5",
day = "29",
doi = "10.1021/jp710893k",
language = "English (US)",
volume = "112",
pages = "7809--7817",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "21",

}

TY - JOUR

T1 - Phosphonic acid modification of indium-tin oxide electrodes

T2 - Combined XPS/UPS/ contact angle studies

AU - Paniagua, Sergio A.

AU - Hotchkiss, Peter J.

AU - Jones, Simon C.

AU - Marder, Seth R.

AU - Mudalige, Anoma

AU - Marrikar, F. Saneeha

AU - Pemberton, Jeanne E

AU - Armstrong, Neal R

PY - 2008/5/29

Y1 - 2008/5/29

N2 - Indium-tin oxide (ITO) electrodes have been modified with both fluorinated alkyl and aryl phosphonic acids [n-hexylphosphonic acid (HPA) and n-octadecylphosphonic acid (ODPA); 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecaf-luorooctyl phosphonic acid (FHOPA), pentafluorobenzyl phosphonic acid (PFBPA), and tetrafluorobenzyl-1,4-diphosphonic acid (TFBdiPA)]. These are modifiers designed to control both wetting properties toward nonpolar molecular solids and to provide a wide range of tunability in effective surface work function. The molecular nature of surface attachment and changes in electronic and wetting properties were characterized by X-ray photoelectron spectroscopy (XPS), UV-photoelectron spectroscopy (UPS), photoelastic modulation infrared reflection-absorption spectroscopy (PM-IRRAS), and contact angle measurements using both water and hexadecane. Interface dipoles from the PA modifiers contribute to shifts in the low kinetic energy regions of UPS spectra (local vacuum level shifts, which translate into changes in effective surface work function). We show that for ITO surfaces modified with FHOPA, and to a lesser extent with PFBPA, the high work function obtained by oxygen plasma cleaning can be maintained after modification, while decreasing the polar component of surface energy. This approach to oxide surface modification is a strategy that may be beneficial for the modification of transparent conducting oxide surfaces in both organic light emitting diodes and in organic solar cells, where oxide/organic compatibility can affect device performance.

AB - Indium-tin oxide (ITO) electrodes have been modified with both fluorinated alkyl and aryl phosphonic acids [n-hexylphosphonic acid (HPA) and n-octadecylphosphonic acid (ODPA); 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecaf-luorooctyl phosphonic acid (FHOPA), pentafluorobenzyl phosphonic acid (PFBPA), and tetrafluorobenzyl-1,4-diphosphonic acid (TFBdiPA)]. These are modifiers designed to control both wetting properties toward nonpolar molecular solids and to provide a wide range of tunability in effective surface work function. The molecular nature of surface attachment and changes in electronic and wetting properties were characterized by X-ray photoelectron spectroscopy (XPS), UV-photoelectron spectroscopy (UPS), photoelastic modulation infrared reflection-absorption spectroscopy (PM-IRRAS), and contact angle measurements using both water and hexadecane. Interface dipoles from the PA modifiers contribute to shifts in the low kinetic energy regions of UPS spectra (local vacuum level shifts, which translate into changes in effective surface work function). We show that for ITO surfaces modified with FHOPA, and to a lesser extent with PFBPA, the high work function obtained by oxygen plasma cleaning can be maintained after modification, while decreasing the polar component of surface energy. This approach to oxide surface modification is a strategy that may be beneficial for the modification of transparent conducting oxide surfaces in both organic light emitting diodes and in organic solar cells, where oxide/organic compatibility can affect device performance.

UR - http://www.scopus.com/inward/record.url?scp=45149085353&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=45149085353&partnerID=8YFLogxK

U2 - 10.1021/jp710893k

DO - 10.1021/jp710893k

M3 - Article

AN - SCOPUS:45149085353

VL - 112

SP - 7809

EP - 7817

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 21

ER -