Indium potential diagram, 407-8

The potential diagram for indium in acidic solution (pH = 0) is given below with standard redox potentials given in V ... 

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. 

As mentioned above, the operation of the device requires that electrons and holes be injected from opposite electrodes. Electrons are injected into the conduction band states of the polymer, and holes into the valence band states, and for a diode formed with a polymer such as PPV, a schematic energy level diagram as shown in Fig. 29.9 is considered appropriate. Note that there are barriers at the electrodes for injection of both electrons and holes from the aluminum and indium-tin oxide electrodes, respectively. It is difficult to make accurate predictions about the barriers to electron and hole injection (J e and respectively, in Fig. 29.9). Making reasonable assumptions about the polymer ionization potential and electrode work functions, it is clear that the barrier to injection of electrons from aluminum must be significantly larger than the barrier to injection of holes from ITO [90]. The majority of the current is therefore expected to be due to holes. Electroluminescence, however, requires the simultaneous injection of electrons, and the quantum efficiency will therefore depend strongly on the barrier to electron injection. 

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