Hopping organic materials

Fishchuk II, Kadashchuk A, Bassler H, Abkowitz M (2004) Low-field charge-carrier hopping transport in energetically and positionally disordered organic materials. Phys Rev B 70 245212... 

Coehoom R, Pasveer WF, Bobbert PA, Michels MAJ (2005) Charge-carrier concentration dependence of the hopping mobility in organic materials with Gaussian disorder. Phys Rev B 72 155206... 

Heterotrophic bacteria have the ability to incorporate not only inorganic N but also dissolved inorganic P into organic material. Additionally, as microbes have extremely high P content relative to plants or even phytoplankton (Kirchman, 1994), HOP may be expected to be at least as or even more important than HON. Studies in lakes and marine systems support the importance of HOP in forming new organic P in aquatic systems (Kirchman, 1994). 

The implications of HOP for quality of organic matter, including quality of DOM, are similar to those of HON (discussion below) as the P content of organic material is often cited as an important determinant of organic matter quality (Sterner, 1995). HON has additional implications for stable isotope research, however, that do not apply to HOP. 

In crystalline organic solids such as anthracene, in which the mobility is on the order of 1 cm2/Vs, the transport mechanism may still be explained by a band theory formalism. But for most organic solids (especially if disordered), the mobility values are far below the lower limit value and a hopping transport mechanism seems to be more appropriate. Organic polymers are classic examples of hopping transport materials. In poly-iV-... 

Schematic diagram depicting the factors causing the discrepancy between TFT and TOF mobilities. In (a), DOS of the organic material is broadened by the polar insulator surfece. In (b), the surface roughness of gate dielectric may affect charge hopping distances.

Charge transport in an organic material is believed to be governed by a hopping process that involve a redox reaction of the charge transport molecules. Cyclic voltammetry (CV) is a preliminary characterization method to determine the redox properties of polymeric materials. One pair of redox waves was observed in these polymers. As shown in Fig. 2.11, polyimide DADT/DSDA... 

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