ROOM TEMPERATURE TIME‐RESOLVED IN μs RANGE DELAYED LUMINESCENCE OF CHLOROPHYLL a AND CHLOROPHYLL‐LUTEIN MIXTURE SOLUTIONS

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Abstract
References: Using time‐resolved in μS range luminescence spectroscopy, we observed at 20°C the emission of chlorophylla,pheophytinaand chlorophyll a‐lutein mixture solutions. This delayed emission exhibits several maxima in the650–750 nm region. The positions and kinetics of decay of delayed emission bands depend on chlorophyll concentration, and vary as a result of pheophytinization and addition of lutein. Our results can be explained by supposition that upon excitation, charge transfer species are formed in various pigment complexes. The back electron transfer reactions yield chlorophyll excited singlet states contributing to observed delayed emission. Delay in emission seems to be due also to the trapping of excitation on the triplet states of various forms of pigment and its detrapping with the participation of thermal energy followed by energy transfer to the forms of pigment characterized by different decay times.