Organic semiconductor current-voltage characteristics

Fig. 10.23. The frame on the left shows current-voltage characteristics of an n-channel transistor formed with electrodes patterned by nanotransfer printing. Laminating these electrodes against a substrate (PET) that supports an organic semiconductor (FCuPc), a gate dielectric (GR) and a gate (ITO)...

Fig. 10.24. Current-voltage characteristics from a nanoscale organic transistor formed by contact of a metal coated stamp against a thin film of the organic semiconductor pentacene. The gate voltage varies between +1.0 V and...

In this section we discuss a method of controlled material degradation for individual organic semiconductors and also for the blends used in bulk heterojunction solar cells [37]. The degradation is studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and by determining current/voltage characteristics (I/V measurements) of the devices. 

As with all optoelectronic semiconductor devices, the current-voltage characteristics of an organic solar cell can be modelled using the continuity equations for each charge type. For electrons in the steady state we have... 

The properties of energetically-distributed charge-carrier traps are above all in disordered organic semiconductors of considerable significance for the analysis of real current-voltage characteristics. We consider the following two energy distributions for shallow traps an exponential distribution, with its maximum at the transport level Ee (compare Fig. 8.6) ... 

Figure 29. For the latter case, it is considered that the semiconducting re-electron systems are separated by insulating hydrocarbon spacers, resulting in alternate thin layers of organic semiconductor and insulator in these monolayer assemblies. The direct current - voltage (I - V) characteristics were mea- sured for the multilayers H2Pc(R)8 and Cu-Pc(R)8 in directions perpendicular and parallel to the film plane. In both cases, the linear I - V relationships of Ohm s law were observed at low electric field and obtained DC conductivities are summarized in Table 3. The normal conductivity (ajJ were ca. 10 13 S cm-1, while the lateral ones p//) were 3.4 x 10-7 and 9.9 x 10 7 S cm 1 for films of the metal-free and copper Pc derivatives, respectively. The former (ojJ tended to decrease slightly with increase of Figure 29. Schematical illustration of the substituent alkyl chain length,...

A number of authors (4-8) have studied the phenomena connected with the injection of current carriers in organic semiconductors. It was established that when equal electrodes are used the current does not depend on the polarity of the applied voltage. When the electrodes are different the I/V characteristics become non-linear and the degree of non-linearity depends on the sign of the potential of one of the electrodes. 

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