Molecular hole transporters

A key issue in hole transporter molecule stability has been found to be the degree of crystallinity of the molecules and the grain size once crystallization occurs. Reduction 

Fortunately, charge injection degradation can be reduced at least in some devices. One common method is to introduce a cascade of materials with increasing HOMO binding energies, breaking the total energy barrier for injection of holes into a series of smaller steps. Many different materials are used in these cascades. Some examples appear elsewhere in this chapter. 

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Snaith HJ, Gratzel M (2007) Light-enhanced charge mobility in a molecular hole transporter. Phys Rev Lett 98 177402... 

In moleculady doped polymers, charge transport is carried out by the hole-transporting molecular dopants, usually aromatic amines. The polymer merely acts as a binder. The hole mobiUty is sensitive to the dopant concentrations. For example, the hole mobiUty of... 

Another approach to molecular assembly involves siloxane chemistry [61]. In this method, the electrically or optically active oligomers are terminated with tii-chlorosilane. Layers are built up by successive cycles of dip, rinse, and cure to form hole transport, emissive, and electron transport layers of the desired thicknesses. Similar methods have also been used to deposit just a molecular monolayer on the electrode surface, in order to modify its injection properties. 

C. Adachi, K. Nagai, and N. Tamoto, Molecular design of hole transport materials for obtaining high durability in organic electroluminescent diodes, Appl. Phys. Lett., 66 2679-2681 (1995). 

Due to its direct relation to Section VI, we begin with a cell in which mainly the hole transporting properties of molecular glasses are used the solid-state dye sensitized cell. 

Keywords Electron transfer Hole transport Hopping Superexchange Couphng to the molecular surroundings... 

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