Charge capture

Jonah et al. [178] found that the fluorescence emitted by 9,10-diphenyl-anthracene (or by p-terphenyl) in cyclohexane solution after photostimulation with Cerenkov radiation both grew-in and decayed more rapidly than when the solution was pulse-radiolysed (see Fig. 34). The delay in the formation of the aromatic excited state ( 0.5 ns) was attributed to the slowness of charge capture and of diffusion together of ions to form an excited state (Sect. 3.4). 

This paper reports a precision measurement of the Lamb shift in the n=2 state of hydrogen using separated oscillatory fields in conjunction with a fast atomic beam. Atoms in the 2 S 2 metastable state are produced through charge capture by protons in a gas target. The atoms pass thrugh two separated oscillatory fields whose relative phase is switched between 0 and ir. A rf quenching field and a solar blind... 

Electronic accumulation represents probe interaction within electric fields. Small electrodes are arranged in an array and are addressed by electric circuits. Thus, charged capture probes are mutually attached or appealed in the discharged flow-through cell [50]. The capture probe concentration is enhanced on positive or negative electrodes. Nanogen uses Streptavidin coated gold electrodes to couple biotinylated capture probes after electronic accumulation (Fig. 18). 

Key n, carrier densities in solid phase, and ion densities in liquid w, charge capture rates and r, rate of diffusion of ions across the potential barrier. (Reproduced, with permission, from Ref. 122. Copyright 1977, American Institute of Physics.)... 

Fig. 2.1 Illustration of the two mechanisms for electron-hole capture discussed in the text. Electrons and holes are transported through their respective transport materials and accumulate at the heterojunction, a) Injection of one of the charges into the opposite polymer makes possible charge capture within the polymer bulk and formation of intramolecular excitons. b) Barrier-free electron-hole capture...

TFB(50 nm)/anode device assuming charge capture via charge injection (a) and barrier-free capture into an exciplex (b). When assuming barrier-free capture, much lower electric fields and charge densities are required at the heterojunction. Graph copied directly from [53]. 

This means that in these blends the spectral shape of the electroluminescence would be independent of whether process (a) or (b) in Fig. 2.1 occurs because ex-citons could quickly transfer towards a nearby interface site. In well-mixed blends it is therefore impossible to show that the exciplex is the primary product of charge capture and hence to prove that barrier-free capture occurs. We address these concerns here by presenting electroluminescence measurements from bilayer light-emitting diodes, where leakage currents are prevented, while a low density of interface sites (in fact the lowest possible) is maintained. 

Fig. 2.46 III ustration of exciton retrapping at PFB F8BT heterojunctions. An exciplex state that was formed at the heterojunction via barrier-free charge capture (Section 2.2) or relaxation of an interfacial geminate pair (Section 2.3) can either decay radiatively and emit (1) or transfer endothermically to the bulk...

Water molecules are well known PL quenchers due to the energy transfer or charge capturing. A short-chain hydrophilic molecule like 2-aminoethanethiol, cysteine, mercaptoacetic acid does not shield the surface of nanocrystals from physi- or chemisorption of water molecules. By contrast, long-chain mercaptoundecanoic acid more effectively protects the surface of nanocrystals which results in less than twofold decrease of PL intensity during the solubilization. 

Not only does protein surface charge capture one layer of water, but, due to the dipolar nature of the water molecule, its influence extends outward through many water layers. Evidence has accumulated that indicates that water may be stratified to distances of 400-500 layers of single water molecules (Pollack, 2001). Thus, cellular water is different from bulk water cellular water is highly... 

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