Temperature dependence of the triplet exciton yield in fission and fusion in tetracene

Journal Article · Sat Aug 01 04:00:00 EDT 1981 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.442164· OSTI ID:6463480

Arnold, S; Whitten, W B

The increase in quantum efficiency for luminescence with increasing excitation intensity is measured as a function of temperature in tetracene. The results indicate that the quantum efficiency for the production of triplets from an excited singlets decreases markedly below 300 /sup 0/K. This decrease is accounted for by a process which competes with exciton fission with a rate K = (1.3 +- 0.2) x 10/sup 8/ sec/sup -1/. This value is shown to be inconsistent with a singlet trapping interpretation for the nonexponential decays found by others in the prompt fluorescence. The results are consistent with a nearly temperature independent value for the fraction of exciton fusion events which lead to excited singlets f. The relative constancy of f above 300 /sup 0/K implies that fusion resulting in a triplet proceeds via the first excited triplet. This in turn provides a qualitative explanation for the apparent lack of a relationship between the measured value of f and the rudimentary value inferred from spin statistics.

• Research Organization: Department of Physics, Polytechnic Institute of New York, Brooklyn, New York 11201
• OSTI ID: 6463480
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 75:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ANALYTICAL SOLUTION
AROMATICS
AUGMENTATION
BRIGHTNESS
CONDENSED AROMATICS
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EXCITATION
EXCITONS
HYDROCARBONS
LUMINESCENCE
MEDIUM TEMPERATURE
MULTIPLETS
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
QUASI PARTICLES
TEMPERATURE DEPENDENCE
TETRACENE
TRIPLETS