Organometallic chemistry at the interface with materials science

Schwartz, Jeffrey; Gawalt, Ellen S.; Lü, Gang; Milliron, Delia J.; Purvis, Kathleen L.; Woodson, Steven J.; Bernasek, Steven L.; Bocarsly, Andrew Bruce; VanderKam, Susan K.

doi:10.1016/s0277-5387(99)00395-2

“…Questions about surface chemical functionality also remain. Some authors claim the presence of surface hydroxyl, 33 justified in part by the observed chemical reactivity of the surface 34 Others claim that the surface concentration of OH is low. 14 HREELS analysis of ITO surfaces cleaned by the method used in this study reveals no sign of surface hydroxyl!…”

Section: Discussionmentioning

confidence: 99%

Phenylphosphonic Acid Functionalization of Indium Tin Oxide: Surface Chemistry and Work Functions

Koh

¹

,

McDonald²,

Holt³

et al. 2006

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The work function of indium tin oxide (ITO) substrates was modified with phosphonic acid molecular films. The ITO surfaces were treated prior to functionalization with a base cleaning procedure. The film growth and coverage were quantified by contact angle goniometry and XPS. Film orientation was determined by reflection/absorption infrared spectroscopy using ITO-on-Cr substrates. The absolute work functions of nitrophenyl- and cyanophenyl-phosphonic acid films in ITO were determined by Kelvin probe measurement to be 5.60 and 5.77 eV, respectively.

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“…Some work − in this area has been done largely or entirely in ultrahigh vacuum (UHV). However, the vast majority of ITO functionalization studies have been performed wet-chemically using a wide variety of reagents including organic and organometallic alkoxysilanes, − amines, − carboxylic acids, ,− organic and inorganic halides, − phosphonic acids, − and thiols 1,22,34,35 as well as bifunctional molecules. ,,,, The bifunctional reagents permit, in principle, subsequent reactions in which the free end is used to anchor another chemical species. In some cases, the adsorbate is implicitly assumed to form a densely packed self-assembled monolayer (SAM) with few if any data provided specifically to characterize the actual structure.…”

Section: Introductionmentioning

confidence: 99%

“…This subject remains controversial, particularly regarding the presence or absence of surface OH groups and their role in the attachment chemistry. In some UHV studies, , the substrate preparation procedure was specifically designed to yield a high OH coverage, which was detectable via X-ray photoelectron spectroscopy (XPS) and infrared (IR) spectroscopy and which was demonstrably involved in the functionalization reaction. On the other hand, for “practical” ITO surfaces (those not prepared and maintained in an atomically clean state in UHV), the surface OH content, its dependence on cleaning procedure, and its correlation with reactivity are uncertain. , Nevertheless, most ITO functionalization studies assume a high coverage of OH as the chemically active sites, often without characterization.…”

Section: Introductionmentioning

confidence: 99%

“…Some work [1][2][3] in this area has been done largely or entirely in ultrahigh vacuum (UHV). However, the vast majority of ITO functionalization studies have been performed wet-chemically using a wide variety of reagents including organic and organometallic alkoxysilanes, [2][3][4][5][6][7][8][9][10][11][12] amines, [13][14][15][16] carboxylic acids, 1,[17][18][19][20][21][22][23] organic and inorganic halides, [24][25][26][27][28][29] phosphonic acids, [30][31][32][33] and thiols 1,22,34,35 as well as bifunctional molecules.…”

Section: Introductionmentioning

confidence: 99%

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Functionalization of Indium Tin Oxide

Bermudez

¹

,

Berry

²

,

Kim

³

et al. 2006

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The preparation and functionalization of ITO surfaces has been studied using primarily X-ray photoemission spectroscopy and infrared reflection-absorption spectroscopy (IRRAS) and the reagents n-hexylamine and n-octyltrimethoxysilane (OTMS). Particular attention has been paid to characterization of the surfaces both before and after functionalization. Surfaces cleaned by ultraviolet (UV)/ozone treatment and subsequently exposed to room air have approximately 0.5-0.8 monolayers (ML) of adsorbed impurity C. Most is in the form of aliphatic species, but as much as one-half is partially oxidized and consists of C-OH, C-O-C, and/or >C=O groups. The coverage of these species can be reduced by cleaning in organic solvents prior to UV/ozone treatment. The OH coverage on the ITO surfaces studied here is relatively small (approximately 1.0 OH nm-2), based on the Si coverage after reaction with OTMS. A satellite feature in the O 1s XPS spectrum, often suggested to be a quantitative measure of adsorbed OH, receives a significant contribution from sources not directly related to hydroxylated ITO. n-Hexylamine adsorbs, at a saturation coverage of approximately 0.08 ML, via a Lewis acid-base interaction. The particular acid site has not been conclusively identified, but it is speculated that surface Sn sites may be involved. For OTMS, a saturation coverage of about 0.21 ML is found, and the C/Si atom ratios suggest that some displacement of preadsorbed organic impurities occurs during adsorption. The alkyl chain of adsorbed OTMS is disordered, with no preferred stereoisomer. However, the chain appears to lie mainly parallel to the surface with the plane defined by the terminal CH3-CH2-CH2- segment oriented essentially perpendicular to the surface.

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Chemically Modified Oxide Electrodes

Ganzorig

¹

,

Fujihira

²

2007

Encyclopedia of Electrochemistry

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The sections in this article are Introduction Electrode Preparation General: Transparent Conducting Oxide Films Cleaning of Substrate Surfaces Cleaning with Solvents Cleaning by Heating and Irradiation Cleaning by Stripping Lacquer Coatings Cleaning in an Electrical Discharge Cleaning Cycles Cleaning of Organic Glass Chemical Methods of Film Deposition Spraying Pyrolysis Chemical Vapor Deposition Sol‐gel Process Physical Methods of Film Deposition Evaporation Sputtering Reactive Ion Plating Pulsed Laser Deposition Other Techniques The Properties of Transparent Conducting Oxide Electrode Surfaces Electrode Modification General SnO 2 ITO ZnO TiO 2 and ZrO 2 Polypyridyl Ru Complexes and Organic Dyes as Sensitizers Short‐chain Alkanoic and Benzoic Acids Long‐chain Organic Acids Other Oxides Organosilanization General Wide Bandgap Transparent Conducting Oxide Electrodes SnO 2 TiO 2 and ZrO 2 ZnO ITO Large Bandgap Oxide Electrodes Potential Applications Tuning the Work Function of Electrodes Correlation of Device Performance with Changes in the Work Function Other Possible Applications SnO 2 ITO ZnO TiO 2 Other Oxides Summary Acknowledgement

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Organometallic chemistry at the interface with materials science

Cited by 8 publications

References 25 publications

Phenylphosphonic Acid Functionalization of Indium Tin Oxide: Surface Chemistry and Work Functions

Phenylphosphonic Acid Functionalization of Indium Tin Oxide: Surface Chemistry and Work Functions

Functionalization of Indium Tin Oxide

Chemically Modified Oxide Electrodes

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