Activation energy zero field

The luminance reaches 100 cd/m2 at 2.5 V with EL efficiency of 2.5 cd/ A. The corresponding external quantum efficiency is about 2% ph/el. At —10 V bias, the photosensitivity at 430 nm is around 90 mA/W, corresponding to a quantum yield of 20% el/ph [135], The carrier collection efficiency at zero bias was relatively low in the order of 10-3 ph/el. The photosensitivity showed a field dependence with activation energy of 10 2 eV [135], This value is consistent with the trap distribution measured in the PPV-based conjugated polymers [136,137],... 

In passing, it should be noted that the reaction between elemental fluorine and hydrocarbons (Step lb in Table 1) is possibly one of the fastest reactions from a kinetic point of view known in any field of reaction chemistry. Studies of the reaction with fluorine to extract a hydrogen from a hydrocarbon or partially fluorinated hydrocarbon in the gas phase found that the activation energy is between 0 and 1 cal mol 1 (not kilocalories). This reaction has been studied independently, with two studies leading to a zero activation energy and one study to a 1 cal mol 1 value. 

Fig. 3.28. Low temperature activation energy versus square root of electric field extrapolated to zero field. The zero field activation energy was found to be Aq = 0.05 eV [54].

Figure 27 The zero-field activation energies of hqle mobilities of binary and ternary mixtures containing a donor and a donor and acceptor in a polymer.

Figure 46 Activation energies for the zero-field hole mobilities of TPD and DEH doped PC.

Schein et al. (1990) measured hole mobilities of TTA doped PC. The temperature dependence was described by an Arrhenius relationship. The results were described by a small-polaron argument, as proposed earlier by Schein and Mack (1988). The dependence of the activation energy on intersite distance is illustrated in Fig. 54. The authors argued that for p < 15 A the results are consistent with adiabatic small-polaron theory while for p > 15 A the results can be described by a nonadiabatic small-polaron argument. Schein et al. derived an expression for the zero-field polaron mobility as... 

Figure 54 The activation energy of the zero-field hole mobilities versus p for TTA doped PC.

Arrhenius relationship. The activation energies were between 0.52 and 0.45 eV for concentrations between 15 and 60%. The concentration dependence of the zero-field mobility was described by a wavefunction decay constant of 1.3 A. The results were described by a small-polaron argument. Based on the concen-... 

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