FET mobility

Fig. 7 Room temperature FET-mobility of P3HT in different microstructures. Downward triangles, spin-coated regioregular film, upward triangles, solution cast film. From [83] with permission. Copyright (1999) by Macmillan Publishers...

Fig. 15 Fits to experimental values of the hole FET-mobility using P3F1T and OCiCio-PPV as active layers. From [100] with permission. Copyright (2007) by the American Institute of Physics...

The transistor performance is generally characterized by field-effect transistor (FET) mobility (j i), current on/off ratio (f n/f0ff), and threshold voltage (Vj)-... 

Table 4.3 summarizes the FET mobility and current on/off ratio data for OTFTs prepared using vacuum deposited indolo[3,2-b]carbazoles (5) as the channel semi-... 

FET mobility measurements thus constitute a sound method for investigating changes in the mobility of an organic semiconductor due to morphology variations. On the basis of the FET characteristics of MDMO-PPV films spin-cast from different solvents, we will discuss the influence of interchain polymer aggregates on the hole field-effect mobility and further consequences for the short-circuiting of solar cells. 

The time of flight (TOF) method has been described in Section 8.4.1. The FET mobility, FE, is obtained from the characteristic of a field effect transistor constructed with the conjugated polymer as the conduction channel see below. With source-drain voltages larger than the gate voltage the source-drain current, Jsd, saturates and is given by ... 

The use of polymers with a low relative permittivity, see Section 2.7, as the FET gate insulator has been found to result in higher carrier mobility and improved device performance (Veres et al., 2003). The authors developed stable semiconductive polymers, poly(triarylamines), and used them to fabricate FETs with silicon dioxide and poly(methylmethacrylate) gate insulators. Values of the carrier mobilities measured in the FETs were about 10 times smaller than those determined by TOF experiments. A dramatic increase in FET mobility was observed when a low permittivity fluoropolymer (e = 2.1) was employed as gate insulator. The FET mobilities for devices with gate insulators with relative permittivities in the range 2-18 are shown in Fig. 10.12(a). The devices were made with two different poly(triarylamines)... 

Comparing the results from different techniques, such as SCLC or FET, each affected similarly by the contact effects, the temperature dependent mobility renders the expected spatial anisotropy of the transport in and normal to the (ab)-plane. The SCLC mobility at room temperature along the c -direction is found to be one order of magnitude smaller than the FET mobility along the (ab)-plane. 

Although some groups have achieved enhanced FET mobility of the SP/IP composite, they somehow proposed different morphological requirements for this enhancement, according to their respective sample preparation conditions. In Table 9.1, the phase evolution routes (tentatively drawn by the author of this chapter,... 

X 10 cm (V s ) at Vds= 30 V. These mobilities are the highest balanced mobilities reported so far for solution processed all polymer bulk heterojunction bipolar FETs. The balanced FET mobilities indicate the presence of sufficient percolation pathways for both charge carriers in these polymer blends. 

Teflon surfaces [31], magnetic fields [32] and isotropic phase dewetting ofpatterned surfaces [33], The best method for extracting the FET mobility from the data depends on the characteristics of the system. 

Although the hexabenzocoronenes have some of the highest PR-TRMC mobilities, they generally align in a planar manner and have proved frustratingly difficult to align in a homeotropic manner. As a result there is very little ToF data to compare with that of other discogens. When FET mobilities have been measured these have usually been at room temperature and in the crystalline phase (Table 3.5). 

The FET mobility //fet can be estimated, either from the linear regime where... 

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