Interfacial layer junction

Fig. 5.3. Formation of a bulk heterojunction and subsequent photoinduced electron transfer inside such a composite formed from the interpenetrating donor/acceptor network, plotted with the device structure for such a junction (a). The diagrams showing energy levels of an MDMO-PPV/PCBM system for flat band conditions (b) and under short-circuit conditions (c) do not take into account possible interfacial layers at the metal/semiconductor interface...

The first significant step towards understanding the mechanism of the electrode-oxide semiconductor is given in an ideal case contact. Another advance in our understanding of the electrode-oxide semiconductor junction is concerned with contacts with surface states, and interfacial layer and... 

In order to evaluate experimental data, an equivalent circuit consisting of three parallel RCs in a serial combination with a contact resistance R, as shown in the inset of Figure 1.53, was used. In the equivalent circuit, the interfacial layers correspond to the junction resistance Ri and R2 and capacitance Cl and Q. Between these depletion layers exists a bulk region represented by a resistor Rb and a capacitance Q,. 

SBSCs may exhibit AMI conversion efficiencies comparable to p-n junction cells when a thin interfacial layer is present at the metal... 

Some of the molecules that are adsorbed on surfaces (especially oxygen and water) strongly interact with the polymer, so chemical reactions can occur at the interface [66], Surface states are formed that can also cause band bending at this interface region and therefore affect the internal electric field [75]. This interface layer seems to hinder the diffusion of gases and metal atoms further into the polymer and the subsequent chemical reaction of the electrode material with the polymer and can therefore be quite important for the operation of the EL devices [76]. The diffusion of the oxygen from the electrode into the polymer that was observed for ITO devices [77] can also be prevented by introducing a thin layer of polyaniline [78]. For real systems the metal/ polymer junction can therefore be understood as an M.v polymer structure, where. v represents an interfacial layer of currently undefined nature. 

Interface between two liquid solvents — Two liquid solvents can be miscible (e.g., water and ethanol) partially miscible (e.g., water and propylene carbonate), or immiscible (e.g., water and nitrobenzene). Mutual miscibility of the two solvents is connected with the energy of interaction between the solvent molecules, which also determines the width of the phase boundary where the composition varies (Figure) [i]. Molecular dynamic simulation [ii], neutron reflection [iii], vibrational sum frequency spectroscopy [iv], and synchrotron X-ray reflectivity [v] studies have demonstrated that the width of the boundary between two immiscible solvents comprises a contribution from thermally excited capillary waves and intrinsic interfacial structure. Computer calculations and experimental data support the view that the interface between two solvents of very low miscibility is molecularly sharp but with rough protrusions of one solvent into the other (capillary waves), while increasing solvent miscibility leads to the formation of a mixed solvent layer (Figure). In the presence of an electrolyte in both solvent phases, an electrical potential difference can be established at the interface. In the case of two electrolytes with different but constant composition and dissolved in the same solvent, a liquid junction potential is temporarily formed. Equilibrium partition of ions at the - interface between two immiscible electrolyte solutions gives rise to the ion transfer potential, or to the distribution potential, which can be described by the equivalent two-phase Nernst relationship. See also - ion transfer at liquid-liquid interfaces. 

Adsorption junctions at the surface of active fillers are of importance due to the large total elastomer-filler interfacial area. The adsorption of chain units at the Aerosil surface causes a significant restriction of local chain motions in the first layer adjacent to the filler surface. The low mobile adsorbed chain units represents another type of network junction in filled elastomers. However, the adsorbed chain units are not rigidly linked to the surface of Aerosil above T. The lifetime of chain imits in the adsorbed state is already very short at room temperature chain units adhere to the filler surface for only tens of microseconds [9], It was shown in Part I that the fraction of adsorbed chain units decreases on heating due to chain desorption. Therefore, the amount of adsorption junctions decreases with the increase of temperature as shown in Fig. 13. 

The competition between the interfacial reactivities, the residual stresses and the elasto-plastic behavior of the components will be strongly dependent on the mechanical stability of the coating-substrate combination. Mechanical stability control has been assessed when making ceramic/metal junctions at high temperature (700°C - 1000°C) during which thick reaction zones tend to form by reactive diffusion in volume intermediate layers. ... 

Under depletion conditions, the withdrawal of majority carriers from the interfacial region of the semiconductor/electrolyte junction creates a space-charge layer consisting of ionised donors (for w-type semiconductors) or acceptors (for p-type semiconductors). The dependence of the space-charge density gs i on the potential... 

---