Charge energetic disorder

To analyze the negative field dependence of the mobihty in EHO-OPPE within the Gaussian disorder transport formahsm and to determine the diagonal (energetic) disorder parameter a and the off-diagonal (positional) disorder parameter d, the following relation between the charge mobihty p and the disorder parameters was employed [75] ... 

Schein LB, Tyutnev A (2008) The contribution of energetic disorder to charge transport in molecularly doped polymers. J Phys Chem C 112 7295... 

Blakesley JC, Greenham NC (2009) Charge transfer at polymer-electrode interfaces the effect of energetic disorder and thermal injection on band bending and open-circuit voltage. J Appl Phys 106 034507... 

In practice, poor charge mobility, energetic disorder, carrier trapping, and physical aberrations comphcate device characterization. The effects of these nonidealities are often modeled according to an equivalent circuit shown in Fig. 12. Incorporating all specific series resistive elements as R, and all specific parallel resistances as R, one obtains the expression... 

Figure 8 The effect of energetic disorder on the dissociation probability of an electron initially created at a distance r0 = 24 A from a fixed positive charge.

Bassler (1984) reexamined Pfister s (1977) data for TPA doped PC. Bassler suggested that the field and temperature dependencies of the mobility could be explained by arguments based on energetic disorder. Bassler extended the same argument to a series of arylalkane derivatives doped into a PC and PS (Pai et al., 1983), and charge-transfer complexes formed between 2,4,7-trinitro-9-fluorenone and poly(N-vinylcarbazole) (Gill, 1972,1976). 

Ries B. and Bassler H., Monte Carlo study of dispersive charge-carrier transport in spatially random systems with and without energetic disorder Phys. Rev. B, 35, (1987) 2295-2302, DOI 10.1103/... 

Vs//2. The energetic disorder o can be imderstood as the width of the Gaussian distribution of the density of energy states for the transport sites the positional disorder E can be treated as the geometric randomness arising from structural or chemical defects [28,29]. In essence, only two material parameters, viz., a and E, are used to describe the randomness of the amorphous organic charge transporter. The PF slope, Ppp, is now replaced with P in Equation 3.7, and in the context of the GDM, it is related to the disorders of tire material. From Equations 3.6 and 3.7, o can be determined from the slope of the plot of p(0,T) vs l/T, while E can be determined from the x-intercept of a plot of P vs (cs/k Tf. 

K. Seki and M. Tachiya, Electric field dependence of charge mobility in energetically disordered materials Polaron aspects, Phys. Rev. B (Condens. Matter Mater. Phys.), 65, 014305 (2001). 

In conclusion, charge transport in amorphous polymers occurs by way of carrier hopping within a positionally random and energetically disordered system of localized states [48]. The dependence of the carrier mobility on diagonal and off diagonal disorder is taken into account by Eq. (2-11) ... 

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