Holes temperature dependence

With the Monte Carlo method, the sample is taken to be a cubic lattice consisting of 70 x 70 x 70 sites with intersite distance of 0.6 nm. By applying a periodic boundary condition, an effective sample size up to 8000 sites (equivalent to 4.8-p.m long) can be generated in the field direction (37,39). Carrier transport is simulated by a random walk in the test system under the action of a bias field. The simulation results successfully explain many of the experimental findings, notably the field and temperature dependence of hole mobilities (37,39). 

Above 2 K, the temperature dependence of the zero-field resistivity of the microbundle measured by Langer et al. [9] was found to be governed by the temperature dependence of the carrier densities and well described by the simple two-band (STB) model derived by Klein [23] for electrons, , and hole, p, densities in semimetallic graphite ... 

Following the general trend of looldng for a molecular description of the properties of matter, self-diffusion in liquids has become a key quantity for interpretation and modeling of transport in liquids [5]. Self-diffusion coefficients can be combined with other data, such as viscosities, electrical conductivities, densities, etc., in order to evaluate and improve solvodynamic models such as the Stokes-Einstein type [6-9]. From temperature-dependent measurements, activation energies can be calculated by the Arrhenius or the Vogel-Tamman-Fulcher equation (VTF), in order to evaluate models that treat the diffusion process similarly to diffusion in the solid state with jump or hole models [1, 2, 7]. 

Figure 12-27. Temperature dependence of the hole mobility in DPOP-PPV at different electric fields Dale for T= 0 have been obtained by extrapolation. The inset shows the intersection of Arrhenius plots at T()=465 K (Ref. 1831).

MIM or SIM [82-84] diodes to the PPV/A1 interface provides a good qualitative understanding of the device operation in terms of Schottky diodes for high impurity densities (typically 2> 1017 cm-3) and rigid band diodes for low impurity densities (typically<1017 cm-3). Figure 15-14a and b schematically show the two models for the different impurity concentrations. However, these models do not allow a quantitative description of the open circuit voltage or the spectral resolved photocurrent spectrum. The transport properties of single-layer polymer diodes with asymmetric metal electrodes are well described by the double-carrier current flow equation (Eq. (15.4)) where the holes show a field dependent mobility and the electrons of the holes show a temperature-dependent trap distribution. 

Figure 12-28. Temperature dependence Figure 12-29. I hotocurrem transient of the 11X3/ of the hole mobility in DPOP-l PV MeLPPP/AI sample after excitation through the ITO ati-...

Many workers have offered the opinion that the isokinetic relationship is confined to reactions in condensed phase (6, 122) or, more specially, may be attributed to solvation effects (13, 21, 37, 43, 56, 112, 116, 124, 126-130) which affect both enthalpy and entropy in the same direction. The most developed theories are based on a model of the half-specific quasi-crystalline solvation (129, 130), or of the nonideal conformal solutions (126). Other explanations have been given in terms of vibrational frequencies involving solute and solvent (13, 124), temperature dependence of solvent fluidity in the quasi-crystalline model (40), or changes of enthalpy and entropy to produce a hole in the solvent (87). 

For the jump of an ion into a hole, a certain energy barrier mnst be overcome with the activation energy A. The rate of this process (or valne of condnctivity) is subject to temperature dependence, according to the well-known Arrhenins equation (see Section 14.1) ... 

Have we pushed the use of time resolved transient absorption with kinetic modeling to its limit We think not. Studies of the temperature dependence of hole transport in hairpins such as 3GAZ should provide additional details about the mechanism of this processes. The use of donor-acceptor triplexes... 

Fig. 2. Surface temperature dependence of the vibrational excitation of NO(v = 0 — 1) in collisions with a clean Ag(lll) surface. The observed thermal activation was attributed to hot electron-hole-pair recombination transferring energy to NO vibration. This work provided some of the first strong evidence that metal electrons can interact with an adsorbate molecule strongly enough to change its vibrational quantum numbers. (See Ref. 24.)...

Jia,., Fujitani, Mv Yae, S., and Nakato, Y., Hole diffusion length and temperature dependence of photovoltages for n-Si electrodes modified with LB layers of ultrafine platinum particles, Electrochim. Acta, 42, 431,1997. 

Fig. 9 Temperature dependence of (a) electron and (b) hole mobilities of an EHO-OPPE film (1=8 pm) measured at =2.0-10 (squares), 3.0-10 (circles), and 4.0-10 Vcm" (triangles). Reproduced with permission from [61]...

Fig. 10 Temperature dependence of the diagonal disorder parameter dfor holes (squares) and electrons (circles). Parameters have been obtained by fitting the experimental data (Fig. 9) to Eq. 1 and Eq. 5. Reproduced with permission from [61]...

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