Bulk loss mechanisms

C) In Ref. 79 the phenomenon of ion rattling motions was supposed to influence the recorded absorption band at v > 200 cm-1. It seems that without a theory capable of describing the whole 0- to 1000-cm 1 band it is hardly possible to assign the measured alteration of absorption due to a number of specific physical factors. The model, presented above, can be used as a basis for this purpose. However, to achieve this aim, a few important factors should additionally be accounted for. (a) It appears that first of all it is reasonable to introduce an additional fraction containing water molecules of a hydration sheath around an ion. The dielectric response of this fraction should differ from that of bulk water, (b) A model of an ion-dipole system suggested by the authors in GT, p. 318, could possibly be employed for this studies, (c) Another important task concerns development of a model describing the specific loss mechanism due to vibration of H-bonded molecules. 

REELS provides information concerning higher energy loss mechanisms than HREELS such as plasmons, interband transitions and characteristic energy losses. EXELES is a technique used in TEM (transmission electron microscopes). It provides information similar to EXAFS (X-ray absorption fine structure), (i.e. data regarding the immediate neighbourhood of atoms of certain elements in the sample). EXELES is bulk sensitive. 

FIGURE 10.8 The energy diagram of the photoinduced electron transfer and the main energy loss mechanisms in donor-acceptor bulk heterojunction solar cells. 

The effect of blooming is to remove the restriction on surface loss by forcing the concentration at the polymer surface to the saturation solubility to maintain equilibrium with the precipitate. Thus, the rate of blooming should be controlled entirely by diffusion within the polymer. Obviously, blooming can only occur until the bulk concentration is reduced to saturation once that concentration is reached, evaporation must take over as the loss mechanism. 

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