Singlet exciton migration

Fluorescence techniques have been demonstrated in recent reviews 1( to be powerful methods for obtaining detailed information on the molecular structure of biopolymers and synthetic polymers. The objective of the present review is to concentrate on two aspects of the photophysics of synthetic polymers — excimer formation and singlet exciton migration. Both topics have been considered recently 11 but in less detail. 

One point which can be settled qualitatively, however, is whether singlet exciton migration does in fact occur in the aryl vinyl polymers. It will be shown that available evidence supports energy migration as an important feature of the photophysics of polystyrene (PS), poly(l-vinyl naphthalene) (P1VN), and poly(2-vinyl naphthalene) (P2VN), the homopolymers which are the subject of the majority of the review. 

Wiesenhofer H, Beljonne D, Scholes GD, Hennebicq E, Bredas JL, Zojer E (2005) Limitations of the Forster destaiption of singlet exciton migration the illustrative example of energy transfer to ketonic defects in ladder-type poly(para-phenylenes). Adv Funct Mater 15 155... 

Strong coupling would not be expected for many fluid solvents but weak coupling could lead to energy transfer from solvent to solvent molecule at rates in excess of diffusion rates. This could occur as a result of singlet or even triplet exciton migration. 

Table 2 Various Singlet and Triplet Exciton Migration Parameters in Some Organic Solids...

J-aggregates of amphiphilic pseudoisocyanine (amphi-PIC) dye are also revealed cylindrical geometry [4]. Amphiphilic dye DiD was used as a trap in order to investigate exciton migration efficiency in amphi-PIC J-aggregate [5], for which the first excited singlet level is located 1850 cm lower the bottom of the J-aggregate exciton band. 

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