Indium, electrodeposition

Hardness of the aimealed metals covers a wide range. Rhodium (up to 40%), iridium (up to 30%), and mthenium (up to 10%) are often used to harden platinum and palladium whose intrinsic hardness and tensile strength are too low for many intended appHcations. Many of the properties of rhodium and indium. Group 9 metals, are intermediate between those of Group 8 and Group 10. The mechanical and many other properties of the PGMs depend on the physical form, history, and purity of a particular metal sample. For example, electrodeposited platinum is much harder than wrought metal. 

Aqueous Electrodeposition. The theory of electro deposition is well known (see Electroplating). Of the numerous metals used in electro deposition, only 10 have been reduced to large-scale commercial practice. The most commonly plated metals are chromium, nickel, copper, zinc, rhodium, silver, cadmium, tin, and gold, followed by the less frequendy plated metals iron, cesium, platinum, and palladium, and the infrequendy plated metals indium, mthenium, and rhenium. Of these, only platinum, rhodium, iddium, and rhenium are refractory. 

Indium and antimony The electrodeposition of In on glassy carbon, tungsten, and nickel has been reported [26]. In basic chloroaluminates, elemental indium is... 

Copper-indium diselenide, CuInSe2 (CIS), is a widely electrodeposited compound, due to its significance in thin film photovoltaics. 

A procedure involving (a) the deposition of nearly stoichiometric films of copper and indium on suitable substrates using vacuum evaporation or electrodeposition and (b) the heat treatment of Cu-In films in a hydrogen-selenium atmosphere at temperatures above 630 °C was reported to yield large grain (several mm in size), stoichiometric thin films of chalcopyrite CIS with a preferred 112 orientation [167]. 

In searching to formulate a mechanism of CuInSc2 phase formation by one-step electrodeposition from acid (pH 1-3) aqueous solutions containing millimolar concentrations of selenous acid and indium and copper sulfates, Kois et al. [178] considered a number of consecutive reactions involving the formation of Se, CuSe, and Cu2Se phases as a pre-requisite for the formation of CIS (Table 3.2). Thermodynamic and kinetic analyses on this basis were used to calculate a potential-pH diagram (Fig. 3.10) for the aqueous Cu+In-i-Se system and construct a distribution diagram of the final products in terms of deposition potential and composition ratio of Se(lV)/Cu(ll) in solution. 

Electrodeposition of copper indium disulfide (CulnS2) has been reported [180-182], In a typical instance, single-phase polycrystalline CuInS2 thin films composed of 1-3 fim sized crystallites were grown on Ti by sulfurization of Cu-ln precursors prepared by sequentially electrodeposited Cu and In layers [183]. In this work, solar cells were fabricated by electrodepositing ZnSe on CuInS2. Cyclic... 

Li KW, Meng XT, Liang X, Wang H, Yan H (2006) Electrodeposition and characterization of PbSe films on indium tin oxide glass substrates. J Solid State Electrochem 10 48-53... 

Cachet H, Cortes R, Eroment M, Mamin G (1997) Epitaxial electrodeposition of cadmium selenide thin films on indium phosphide single crystal. J Solid State Electrochem 1 100-107... 

Since indium is one of the most effective metals for electrochemical reduction of C02, n-Ti02 on which indium had been electrodeposited was examined.92 Enhancement of the faradaic efficiency of C02 reduction by one order of magnitude or more compared to that at undoped n-Ti02 was observed, but the product detected was mainly hydrogen with a small amount (<5%... 

Substrates DME = dropping mercury electrode FTO = fluorine-doped tin oxide G = graphite GC = glassy carbon GrC = graphic carbon ITO = indium tin oxide-coated glass SC = single crystals SS = stainless steel TCO = transparent conducting oxide VC = vitrious carbon. Miscellaneous ECALE = electrochemical atomic layer epitaxy ED = electrodeposition ML = monolayer RT = room temperature SMD = sequential monolayer deposition V = vacuum. 

Figure 27. Schematic for solid-state electrical measurements with ultrathin polymer separators electrodeposited onto planar indium—tin oxide (ITO) or Au substrates. The top electrode makes a soft contact with the polymer by slow evaporation of Au or direct contact with a liquid metal (either Hg or Gain eutectic) using a micrometer-controlled syringe to control the approach to contact. Measurements are made in an argon-filled glovebox to minimize effects of O2 and H2O.

Ferrocenyl dendrimers also afford electroactive films on indium tin oxide (ITO) electrodes in the same manner as described above. UV-visible spectroelectro-chemical measurements of this modified electrodes on oxidation show changes characteristic for the formation of fenocenium cations. Thus, Figure 8 shows the UV-visible absorption spectrum of a film of 2 electrodeposited on a transparent ITO electrode, which exhibits a strong band at 260 nm and a weak absorption band centered at 600 nm, which agree with those observed for the cationic dendrimer [2 KPF j ]g in solution described above. 

The electrodeposition of CdS films on conductive substrates from aqueous solutions is a low-cost process, which is well suited for the preparation of film solar cells. Polycrystalline CdS films of good quality were obtained by electrolysis with rectangular voltages on indium... 

Electrodeposition on transparent material such as indium tin oxide (ITO) can be used for electrochromic applications [328]. Pb deposition on indium-tin oxide electrode occurs by three-dimensional nucle-ation with a diffusion-controlled growth step for instantaneous nucleation [329], and the electrode process has also been studied using electrochemical impedance spectroscopy [328]. 

In our opinion the electrodeposition of selenium is quite promising for a variety of applications. For example, the possibility to deposit grey selenium, indium, and copper in one ionic liquid at variable temperatures might be regarded as the first step in making selenium-containing compound semiconductors like CIS by electrochemical means. 

The electrodeposition of indium. In, has been reported in a basic DMPICl—AICI3 ionic liquid [24]. Indium trichloride, InCl3, dissolves in the basic ionic liquid and forms a trivalent indium chlorocomplex anion, InClj, which can be reduced to metallic In by a three-electron transfer reaction ... 

The electrodeposition of antimony [77] and indium-antimony [78] alloys has been reported in a basic EMICI-EMIBF4 ionic liquid. Antimony trichloride, SbCl3, dissolves in the ionic liquid and forms SbQ, the same as in the basic chloro-aluminate ionic liquid. Metallic Sb can be obtained by the cathodic reduction of SbCl4, as shown in Eq. (9.14). The formal potential of Sb(III)/Sb is reported as —0.27 V vs. AI/Al(in) in the ionic liquid containing Cl at 0.11 M. In addition the oxidation of SbCl4 leads to the formation of a pentavalent antimony species, SbClg ... 

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