Coadsorption of cesium and iodine on Pt(111): Structure and ionicity

Drnec, Jakub; Harrington, David A.

doi:10.1016/j.susc.2010.08.026

Cited by 2 publications

(19 citation statements)

References 41 publications

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“…As electropositive adsorbates, electron transfer to the surface is significant, or there can be electron transfer to electronegative adsorbates, which leads to the interesting possibility of ionic layers. Our work on Cs-modified Pt(111) identified a strongly-bound low-coverage state of Cs + that directly desorbs as the ion [4], and the interaction of this and higher coverage Cs with iodine showed evidence for ionic layers [5]. According to Wang et al [6], only a few hexagonal arrangements are favorable for planar ionic layers on (111) surfaces, and our LEED studies of the Cs-I coadsorption system found such structures.…”

Section: Introductionmentioning

confidence: 49%

“…The break in slope of the WF ("kink") occurring between about −18 to −3 eV has been previously assigned to the phase transition from the anomalous (Cs + ) to the normal (neutral Cs) adsorption state [4,27]. After reaching a minimum, corresponding to the Pt(111)(2 × 2)-Cs structure ( Cs = 025) [4,5,14,28], the WF increases and then levels off as the surface saturates. (After the Cs doser is turned off, the WF slightly decreases, e.g., after 650 s in Fig.…”

Section: Adsorption Of Cs and Coadsorption With Oxygen Or Iodinementioning

confidence: 99%

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Oxygen and iodine adsorption on cesium-precovered Pt(111)

Drnec

Harrington

2014

Surface Science

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The adsorption behavior of oxygen and iodine on a Cs-precovered Pt(111) surface is studied with Low Energy Electron Diffraction (LEED), thermal desorption spectroscopy (TDS) and work function measurements. TDS shows multiple oxygen desorption states that depend on Cs coverage, with both atomic and molecular oxygen desorbing from the surface. Cs is stabilized by oxygen relative to Cs on Pt(111), and most is retained on the surface until the last oxygen desorbs. Atomic arrangements are proposed for two (4 × 4)-Cs,O structures observed by LEED, and these are similar to Cs,I structures with ionic character. At the highest oxygen and Cs coverages, there is evidence for a molecular oxygen state above room temperature. Dosing iodine on Pt(111)-Cs,O results in substitution of O by I in Cs,O islands. Oxygen adsorption on a Cs-saturated Cs monolayer at 295 K causes an initial work function decrease consistent with underlayer adsorption, i.e., with O adsorption below the plane of the Cs atoms. This feature is absent for adsorption on the lower-coverage Pt(111)(2 × 2)-Cs surface.

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Section: Introductionmentioning

confidence: 49%

Section: Adsorption Of Cs and Coadsorption With Oxygen Or Iodinementioning

confidence: 99%

Oxygen and iodine adsorption on cesium-precovered Pt(111)

Drnec

Harrington

2014

Surface Science

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“…The fact that the ionic layers organize into very defined arrangements is not a surprise, as suggested by standard electrostatic calculations taking into the account the image charges in the metal substrate (7,13). These calculations show that, depending on the electrostatic charge of each atom and on the distance from the surface, only a few surface stoichiometries are favorable, namely Cs2I and CsI where the overall electrostatic energy is minimized.…”

Section: Resultsmentioning

confidence: 91%

“…To further test the proposed hypothesis, we prepared binary layers from highly electropositive cesium and electronegative iodine or oxygen deposited on Pt(111) (13,14). According to the previous observations, the resulting ionically bonded layers are expected to have a mixed monolayer structure.…”

Section: Resultsmentioning

confidence: 98%

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From Salt to Germanene: A Cookbook for Electrochemical Formation of 2D Materials (Inspired by R. Adžić)

Drnec

Stickney²,

Harrington

2018

ECS Trans.

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2D materials with honeycomb lattices are increasingly studied due to their unique electronic and mechanical properties. The typical preparation techniques, such as chemical vapor deposition and cleavage of bulk crystals, are either complicated or limited to only certain classes of materials. Here we discuss basic ordering principles in 2D monoatomic layers and show that electrochemical deposition can also result in 2D films with desired honeycomb structures. The principles are first studied on model ionic 2D layers prepared in ultrahigh vacuum. Two ordering possibilities are identified: a bilayer structure for covalently bonded films and a mixed monolayer structure for ionically bonded films. Typically, the most energetically favorable configuration in mixed layers is when ions with one polarity are closely surrounded by ions of the opposite polarity. This translates into a layer with honeycomb structure on substrates with p6/p3 symmetry. This phenomenon can be used to prepare germanene, a layer with such a structure.

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Coadsorption of cesium and iodine on Pt(111): Structure and ionicity

Cited by 2 publications

References 41 publications

Oxygen and iodine adsorption on cesium-precovered Pt(111)

Oxygen and iodine adsorption on cesium-precovered Pt(111)

From Salt to Germanene: A Cookbook for Electrochemical Formation of 2D Materials (Inspired by R. Adžić)

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