Sensitized charge carrier injection into organic crystals studied by isotope effects in weak magnetic fields
✍ Scribed by W. Bube; M.E. Michel-Beyerle; R. Haberkorn; E. Steffens
- Publisher
- Elsevier Science
- Year
- 1977
- Tongue
- English
- Weight
- 498 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
The magnetic field (H = 50 Oe) dependence of the rhodamine sensitized triplet exciton density in anthracene crystals is influenced by isotopic substitution. This confirms the hyperfine interaction as mechanism explaining the change of the spin multiplicity in the initially formed singlet state of the radical pair. The isotope effect occurs in the sensitizing dye ('4N/15N) rather than at the molecular site of the injectedcharge within the crystal. This can be understood in terms of the high hopping frequency of the charge carriers as compared to the time constant of the hyperfiie induced singlet-triplet transition. Since the dye molecules adsorb in an oriented fashion, the angular dependence of the magnetic field modulation of the triplet csciton density can be interpreted without assuming any additional interactions.