Triplet exciton caging in two dimensions: Magnetic field effects

S. Arnold, C. E. Swenberg, M. Pope

Research output: Contribution to journalArticle

Abstract

Magnetic field dependence of the room temperature prompt fluorescence under high field conditions from mixed crystals of tetracene containing 2,3- benzocarbazole (BC) as guest molecules is studied both as a function of the mol fraction of BC and the orientation of the external magnetic field. Crystalline mixtures of BC in tetracene were prepared in the mol fraction range 0%-48.1%. For mol fraction x<9% BC, the angular separation between the high field pair state resonances was approximately 52°, whereas for x∼9% this separation dropped to ∼41% and remained at this value for concentrations 9.4%<x<29.0%. This experimental result is interpreted as indicating that the mixed crystal system BC/tetracene undergoes a crystallographic phase transition for x∼9%. An analysis of both the "on" and "off" field resonance enhancement in the prompt fluorescence of the host is shown to be consistent with previously reported increase in the fluorescence lifetime with x and existing pair state theory of the magnetic field effects on exciton fission provided the fission branching ratio, ε, is a function of the BC concentration. For x>9%, ε is a monotonic increasing function of x which is interpreted as an enhancement of the geminate recombination rate of the original triplet exciton fission pair due to presence of exciton reflectors that reduce the size of the domain in which the excitons can freely move.

Original languageEnglish (US)
Pages (from-to)5115-5120
Number of pages6
JournalThe Journal of chemical physics
Volume64
Issue number12
StatePublished - 1976

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Magnetic field effects
excitons
magnetic fields
Magnetic fields
mixed crystals
Crystal orientation
reflectors
fission
Fluorescence
Crystalline materials
fluorescence
Crystals
Molecules
augmentation
room temperature
LDS 751
molecules
Temperature
naphthacene

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Triplet exciton caging in two dimensions : Magnetic field effects. / Arnold, S.; Swenberg, C. E.; Pope, M.

In: The Journal of chemical physics, Vol. 64, No. 12, 1976, p. 5115-5120.

Research output: Contribution to journalArticle

Arnold, S. ; Swenberg, C. E. ; Pope, M. / Triplet exciton caging in two dimensions : Magnetic field effects. In: The Journal of chemical physics. 1976 ; Vol. 64, No. 12. pp. 5115-5120.
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