Hole-transporting materials OLED application

NUY 02] Nuyken O., Bacher E., Braig T. et al., Crosslinkable hole- and electron-transport materials for application in organic light emitting deviees (OLEDs) , Designed Monomers and Polymers, vol. 5, nos. 2-3, pp. 195-210, 2002. 

Polysilanes can be part of the active layer or, such as in multi-layered OLEDs, serve as a hole transporting layer. There are a number of publications describing polysilanes as a photoactive layer or as a hole transporting material in organic solar cells but in most of them polysilanes are merely mentioned as a general example of an organic semiconductor. They are, for example, not specified in the published examples of patents and are only included to widen the scope of the claims. Only the publications mentioned below cover the application of polysilanes in organic photovoltaics in more detail. 

Kido et al. have reported the application of polymethylphenylsilane as a hole transporting layer in multi-layer OLEDs. In contrast to the OLED shown in Fig. 23, the emitting layer in these early devices was not a mixture of polymers but was prepared by layer-by-layer deposition of the active materials. In the work by Kido, aluminum-tris(8-hydroxyquinoline) (Alq3) was used as both electron transporting material and emitter. It was applied onto the hole transporting polysilane layer by vacuum deposition [111]. 

Another interesting application is to use phthalocyanines as a hole-injection layer in organic light-emitting diodes (OLEDs). Zhu et al. demonstrated that a SAM of phthalocyanine thiol (HS-Pc) may act as a hole injection material in OLEDs (Fig. 42). The insertion of a SAM of HS-Pc between the Au anode and the hole-transport layers enhances the hole injection, which in-... 

It would be outside of the scope of this review to address all material functionalities for every type of application. The focus is limited to FETs and transport effects in polymeric OFET. Carrier transport is a key property that links materials for all applications. The learning in OLED and OPV devices has been extremely useful in providing guidelines for OFET materials and vice versa. In OLEDs, carriers are injected from the anode and cathode and they move through the polymeric film. Ideally, the rate at which electrons and holes are supplied, i.e., their mobility, should be similar. In OPV cells, carriers are separated and transported to the respective electrodes to create a photocurrent. In OFETs, carriers... 

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