Hole-electron relationship

Hole-electron relationship in spin-orbit coupling... 

Oc = WQ—Eji, here Wv and Wq represent the work function of anode and cathode, respectively. As a consequence, holes (electrons) carmot hop to HOMO (LUMO). However, when bias voltage is applied across the device, HOMO (LUMO) of organic semiconductor will slant, and then the holes (electrons) distributed around Fermi level will have considerable possibility to cross a triangular barrier and get injected into HOMO (LUMO). When the external electric field becomes higher, the energy level will slant badly and the barrier will become lower. The relationship between the current of the device / and the electric field strength E can be demonstrated in Fowler-Nordheim formula ... 

Device efficiency. The device efficiency depends not only on PL efficiency of the emitting polymer but also on the efficiency of hole-electron recombination which is related to Ae charge transporting properties of materials used in the device and to the device structure as described above. Employing a multi-layer device(23) and a Mg-Ag or Li-Al alloy electrode(9), we have already improved the device efficiency but have to further improve the efficiency for commercialization. We, thus, have studied the relationship between composition of the random copolymer and the device efficiency. 

Two types of scattering affect the motion of electrons and holes. Lattice or phonon scattering, resulting from thermal vibrations of the lattice, gives increasing ampHtude of vibration with temperature. The associated mobihty decreases according to the relationship 2"-3/2 second source of... 

Exactly the same equations apply for cases in which the electronic defects dominate the equilibrium, so that Eq. (7.35) still represents the relationship between the hole concentration and partial pressure. The values of the equilibrium constants, however, are now changed. The revised values are ... 

Sometimes, there are just indirect mechanistic relationships, or the existence of completely independent transport paths (e.g., protonic charge carriers and electronic holes in oxides). Parasitic transport frequently limits the fuel-cell performance, and a mechanistic understanding is definitely useful in the development of separator materials. 

Person 1 Use the data to write a relationship for the intrinsic conductivity of this substance as a function of the electron and hole mobilities. 

The conductivity of these materials can be controlled by the number of defects. In a /7-type semiconductor such as CU2O, in which vacancies are formed in the cation lattice when the oxygen partial pressure is increased, we can develop relationships between conductivity and oxygen partial pressure. The overall reaction for the formation of vacancies and electron holes can be written in Kroger-Vink notation (cf. Section 1.2.6.1) as... 

This parameter was determined from xerographic residual potential in a-Sei- Te monolayer films. As one can see, even with very little Te alloying, there is a considerable rise in both hole and electron deep traps. The relationship between the trapping time and the residual potential has been evaluated by several authors (see, for example. Refs. [12, 15]). It can be seen that once the Te concentration exceeds 12 wt% Te, the residual potential is more than an order of magnitude larger than typical values for pure selenium. 

Relationships of other type are observed in the case where both the conjugated reactions proceed through the same band (Fig. 13b). For example, the cathodic reaction (42b) can take place with the participation of valence electrons rather than conduction electrons, as was assumed above. Thus, reduction of an oxidizer leads to the injection of holes into the semiconductor, which are used then in the anodic reaction of semiconductor oxidation. In other words, the cathodic partial reaction provides the anodic partial reaction with free carriers of an appropriate type, so that in this case corrosion kinetics is not limited by the supply of holes from the bulk of a semiconductor to its surface. Here the conjugated reactions are in no way independent ones. 

When the quantum yield is so low that the recombination reaction becomes relatively dominant, Eq. (5.14) is simplified to e = (kekjkrg)l/2, or [e ] = (khg/kIke)l/2. This relationship indicates that the steady amount of photoinduced electron is proportional to the square root of the light intensity. A similar relationship can be also obtained for the case of the photoinduced holes, and an equation similar to Eq. (5.14) is used to calculate the hole transfer yield,[Pg.44]

The above relationship between 0 and the rate constants is derived based on the conventional formulation of the rate equations. The unit to measure the amount of electrons and holes in the particle is density, the same as in bulk semiconductors. When the particle size is extremely small or the photon density is very low, only a few pairs of electron and hole are photogenerated and recombine with each other in the particle. This means that photon density does not take continuous values as suitably used in the conventional rate equations, but takes some series of values whose unit is the inverse of the particle volume. Taking into account this deviation, we proposed a new model in which particles are assigned by two integers, n and m, which represent the numbers of... 

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