Lowest barrier layers

The electrons excited into the different levels within in the single well, could be transferred to an acceptor molecule in the electrolyte either by thermionic emission across the outer barrier layer Otherm) or tunneling through it (Jiun) (F g- 9.33). The photocurrent spectrum does not give any information about whether a hot electron was transferred. The observed structure in these spectra could in principle be caused simply by quantized absorption followed by a complete hot carrier relaxation and electron transfer from the lowest quantum level. 

Electrical measurements on devices with different layer thickness have shown that the diode current depends on the applied field rather than the drive voltage. This is similar to what has been observed with our alternating PPV copolymers [68]. It indicates that field-driven injection determines the electrical characteristics. From Figure 16-39 it is evident that U-OPV5 has the lowest onset for both current and emission. By means of Fowler-Nordhcini analysis of the /-V -charac-teristics and optical absorption measurements, wc estimated the injection barrier for holes and the HOMO-LUMO gap, respectively [119]. The results of... 

Fig. 9 OMT bands for NiOEP, associated with transient reduction (1.78 V) and transient oxidation (—1.18 V). Data obtained from a single molecule in a UHV STM. The ultraviolet photoelectron spectrum is also shown, with the energy origin shifted (by the work function of the sample, as discussed in [25]) in order to allow direct comparison. The highest occupied molecular orbital, n, and the lowest unoccupied molecular orbital, %, are shown at their correct energy, relative to the Fermi level of the substrate. As in previous diagrams,

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