Charge mobility characteristic

Ionic liquids with discrete anions have a fixed anion structure but in the eutectic-based liquids at some composition point the Lewis or Bronsted acid will be in considerable excess and the system becomes a solution of salt in the acid. A similar scenario also exists with the incorporation of diluents or impurities and hence we need to define at what composition an ionic liquid is formed. Many ionic liquids with discrete anions are hydrophilic and the absorption of water is found sometimes to have a significant effect upon the viscosity and conductivity of the liquid [20-22], Two recent approaches to overcome this difficulty have been to classify ionic liquids in terms of their charge mobility characteristics [23] and the correlation between the molar conductivity and fluidity of the liquids [24], This latter approach is thought by some to be due to the validity of the Walden rule... 

A regioregular homopolymer of 3-nonylthieno[3,2-Z>]thiophene was also prepared (Table 17.1, 10) however the molecular weight was low and no evidence of thermal transitions was observed by DSC [51]. Charge transport characteristics were not reported. The homopolymer of 3,6-dimethoxythieno[3,2-f>]thiophene [53] and copolymers of 3,4-dialkoxythieno[2,3-f>]thiophene [54] have recently been reported as a possible alternative to the conducting polymer ethylenedioxythiophene (PEDOT). Co-polymers of thieno[3,2-Z>]thiophene [55-57] and thieno[2,3-f>]thiophene [58] with 9,9-dialkyl fluorene have also been reported for both transistor and OLED applications. In the case of the thieno[3,2-b]thiophene copolymer, the polymer exhibited thermotropic liquid crystalline behavior with a nematic phase at high temperature [59]. p-Type field effect mobilities in transistor devices were on the order of 1 x 10 cm V s . Although the value is on the low side of acceptable performance, a comparison to the well-studied... 

Figure 11.5 shows the carrier mobilities of some typical hole transport materials [182]. It is evident that among film-forming organic photoconductors PEPK has one of the best charge carrier characteristics. PEPK was a commercial product in the former Soviet Union. It was produced industrially by a Latvian company, Biolar, according to Scheme 11.13 [230]. 

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