Ionic liquids on oxide surfaces

Abstract

Ionic liquids supported on oxide surfaces are being investigated for numerous applications including catalysis, batteries, capacitors, transistors, lubricants, solar cells, corrosion inhibitors, nanoparticle synthesis and biomedical applications. The study of ionic liquids with oxide surfaces presents challenges both experimentally and computationally. The interaction between ionic liquids and oxide surfaces can be rather complex, with defects in the oxide surface playing a key role in the adsorption behaviour and resulting electronic properties. The choice of the cation/anion pair is also important and can influence molecular ordering and electronic properties at the interface. These controllable interfacial behaviours make ionic liquid/oxide systems desirable for a number of different technological applications as well as being utilised for nanoparticle synthesis. This topical review aims to bring together recent experimental and theoretical work on the interaction of ionic liquids with oxide surfaces, including TiO2, ZnO, Al2O3, SnO2 and transition metal oxides. It focusses on the behaviour of ionic liquids at model single crystal surfaces, the interaction between ionic liquids and nanoparticulate oxides, and their performance in prototype devices.

In situ XPS of competitive CO2/H2O absorption in an ionic liquid

“…Fundamental studies of ILs at TiO 2 surfaces are sparse so there is very little literature for comparison [16]. Wagstaffe et al studied 4 Å and 30 Å thick films of an imidazolium-based IL at the anatase TiO 2 (101) surface using XPS [52].…”

“…(d) Gas exposure regime for the ESD1 [P66614][124Triz] electrosprayed thin film. [8,9], and solar cells [10,11]), tribology (lubricants [12,13] and corrosion inhibitors [14]) and catalysis (solid catalysts with an IL layer (SCILL) and supported IL phase (SILP) catalysts [15,16]).…”

Ionic Liquid‐Mediated Scanning Probe Electro‐Oxidative Lithography as a Novel Tool for Engineering Functional Oxide Micro‐ and Nano‐Architectures

“…First, the ionic nature of RTILs ensures that they can adsorb on virtually all polar surfaces, including most transition metals and metal oxides as well as various semiconductors. [56][57][58][59][60] Second, RTILs can form well-defined electrical double-layer (EDL) structures at electrified interfaces. [61] These EDL structures can not only provide good interface stability at the electrode surface but also enables efficient transfer of electrons and ions -a critical requisite for the electrochemical reactions for o-SPL.…”

Surface Modification of ITO with N‐Heterocyclic Carbene Precursors Results in Electron Selective Contacts in Organic Photovoltaic Devices

“…Both binding mechanisms either through free carbene or imidazolium-based cations would result in surface dipoles with dipole moments pointing away from the ITO layer, reducing the effective work function of the electrode and thus rendering the contact more electron-selective. [37,38] In the following sections, the effect of ITO electrode modification with IPr-CO 2 and subsequent annealing on the charge carrier selectivity in organic solar cells is investigated. The nature of the bound species is elucidated and a mechanism for binding the material to the ITO surface is suggested based on the applied characterization tools and techniques.…”

“…Alternatively, imidazolium cations could be formed by the interaction of carbene with surface‐bound hydroxyl groups. Both binding mechanisms either through free carbene or imidazolium‐based cations would result in surface dipoles with dipole moments pointing away from the ITO layer, reducing the effective work function of the electrode and thus rendering the contact more electron‐selective [37,38] . In the following sections, the effect of ITO electrode modification with IPr‐CO 2 and subsequent annealing on the charge carrier selectivity in organic solar cells is investigated.…”