Donor layers

Fig. 3 (a) Crystal structure of (DMET)2FeBr4. The dotted and dashed lines denote the intermo-lecular anion—anion and donor-anion contacts, respectively, (b) Fermi surfaces obtained for a donor layer around z = 1/2 using the tight-binding approximation. The solid arrow represents the nesting vector Q (a b )/2... 

Figure 26. Fluorescence decay curves of the donor layer separated by the spacer (Cp) from the acceptor (a)Cl2NC12 and (b)C18NC8, observed at 470 nm.

The material (DMET)2FeBr4 consists of electric quasi-ID chain-based donor layers and magnetic Fe3+ square lattices. The absorption line was observed73 to split at 130 GHz and from the splitting the exchange interaction between (/-electrons and Jt-electrons could be estimated. 

Barrier membrane NO donor layer Protecting layer GOx layer... 

Fig. 7 Schematic representation of the organic-inorganic solid state hybrid synthesized by Mallouk and co-work-ersj209 Absorption of a photon by any of the organic layers results in energy transfer to the electron donor layer.

Figure 1. Donor layers of (BEDO-TTF)5 [CsHg(SCN)4]2 where the different types of chains and donor... donor interactions have been labelled.

This structure differs from those of a-(BEDT-TTF)2MHg(SCN)4 salts with respect to both the donor and acceptor sublattices [7]. The donor layers in the present salt have a P -type arrangement (Fig. 1) and are built from three different BEDO-TTF donors (A, B and C). There are three different types of intermolecular interactions with the slab of organic molecules, the relative orientation of which allows us to describe this layer as being composed of a series of parallel stacks of slipped donors along the (2a-b)-direction, as a series of step-chains along the a+2b) -direction, or as a series of parallel... 

Based on the structure of the donor layers (Fig. 1) of (BEDO-TTF)CsHg, the band structure for these layers was calculated near the Fermi level (Fig.4). As shown in Fig. 1, there are five donors per repeat unit of the layer so that the five bands of Fig. 4 are... 

Figure 5. Calculated Fermi-surface for the donor layers in (BEDO-FFT)5[CsHg(SCN)4]2.

A different combination of blend and bilayer structures can also be quite efficient. Having a mixture of polymers in the donor layer and using Ceo as the acceptor provides a way of increasing the spectrai range of absorption of photovoltaic cells while retaining good collection efficiency [23]. A blend donor layer can also be used to mimic the process of photosynthesis where many... 

A reasonable question to ask is the following. If one layer (the acceptor layer) in CaBe2Ge2 is more stable than the other, the donor layer, why does the CaBe2Ge2 structure form at all Why doesn t it go into a ThCr2Si2 structure based on the acceptor layer alone The answer lies in the balance of covalent and dative interactions for some elements the binding energy gained in donor-acceptor interlayer interactions overcomes the inherent stability of one layer isolated.39c... 

Figure 5.26 shows an LB film that regulates electron transfer. Monolayers of an electron donor layer, an insulating fatty acid layer and an electron acceptor layer were transferred in a defined sequence. In this hetero-layered LB film, electron transfer only occurs from the inside to the outside, and the structure of the insulator layer determines the efficiency of electron transfer. Swapping aroimd the donor layer and the acceptor layer reverses the direction of electron transfer. Simply controlling the layering structure therefore enables us to modulate the direction and efficiency of electron flow. 

Many dye chromphores or reactive groups of electron donors and electron acceptors are hydrophilic and are therefore located at the hydrophilic interfaces of the mixed monolayers. According to the normal structure they are at the same interface or separated by at least two hydrocarbon chains yielding a distance of the order of 50 8 between the interfaces. This is an appropriate spacing between an excited energy donor layer... 

In quantum terms, we may describe the phenomena as follows (see Fig. 14). In the acceptor layer, for example, there would be an anion radical with neighbors on either side with vacant orbitals equivalent to the one occupied by the extra electron. This electron in its migration, i.e., when it moves from one molecule to the next one, produces a state after the reaction [as in (1), Fig. 14] shown in the top row of Fig. 14 which is identical in energy with the starting point. The same thing can be said of the donor layer with its hole, which can have electron migra-... 

The schematic cross section and energy level diagrams of a CuPcCgo PM-HJ cell are shown in Figure 12.14. The active region consists of a pure CuPc donor layer, a mixed CuPcrCgo layer, and a pure acceptor layer successively deposited on the ITO anode. The thicknesses of these three layers are... 

It has been shown that the long alkyl chains in LB films order in a regular manner. On the other hand, no definite information on the orientation of the attached groups is available. Due to the flat shape of the attached donors, strong tc-tc overlap can only be established in one direction. In a simple picture of the donor layer, one would thus have to consider two ordering... 

As shown by its Lewis symbol above and discussed in Chapter 3, each silicon atom has 4 valence electrons. In a crystal of Si, each of the silicon atoms is covalently bonded to four other Si atoms, as shown in Figure 8.13. If a B atom replaces one of the Si atoms, the 3 valence electrons in B result in a shortage of 1 electron, leaving what is called a positive hole. Each As atom has 5 valence electrons, so that replacement of one of the Si atoms by As leaves a surplus of 1 electron, which can move about in the Si crystal. A layer of Si atoms doped with As makes up a donor layer because of the extra valence electron introduced by each As atom, and Si doped... 

What is meant by a positive hole in the acceptor layer of Si in a solar cell What distinguishes the donor layer ... 

---