Long-lived charge separation, increased

Tb confirm the long-lived charge separation by the lateral diffusion mechanism, we also measured the surface potential change on alternate LB films containing A-S dyads similar to types a and b. Tb increase singnal intensities, both types of LB films contained 30 bilayers of the alternate monolayers. As shown in Figs. 19a and... 

The rate of energy and electron transfer in any of these systems is an ensemble average of all sites within the layered assembly, and thus there is no single rate for any of the processes in the assemblies. Nonetheless, in addition to the increased quantum yield, assemblies constructed with the HTiNbOs spacer exhibit a long-lived charge-separated state component not observed in the a-ZrP spaced assemblies, of x = 900 ps. While there is still much to be learned from the study of multi-chromophore arrays, this synthetic approach appears to hold much promise for the creation of organic-inorganic hybrid solid state devices. 

Q and C-P-Q species discussed above, we may ascribe this transient to the species C -P-Qa-Qb - The quantum yield of this long-lived charge-separated state was found to be 0.23 at ambient temperatures. Cooling the sample to 240 K resulted in an increase in quantum yield to O.SO. 

TTie main conclusion from our experiments is that Cl-depletion renders PSII very sensitive to photodamage even at light intensities were no or very little photoinhibition is observed in normal thylakoids. The most likely explanation for this increased sensitivity is that the continuous illumination leads to the formation of long lived highly oxidizing radicals on the donor side of PSII. In Cl-depleted thylakoid membranes the S2 to S3 transition is blocked. Thus, one electron can be taken from the Mn-cluster and probably one more from tyrosine (18). Therefore, only one or two normal reductions of P680 place. Then the next charge separation leads... 

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