Triplet photophysical properties of poly(N-vinylcarbazole) in fluid solutions and in solid films in the submicrosecond time regime

Journal Article · Mon Jan 01 00:00:00 EST 1990 · Macromolecules; (United States)

DOI:https://doi.org/10.1021/ma00203a021· OSTI ID:7109807

Chakraborty, D K; Burkhart, R D ^[1]

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1. Univ. of Nevada, Reno (United States)

Triplet photophysical properties of poly(N-vinylcarbazole) (PVCA) have been examined in fluid solutions and in solid films using time resolution of a few hundred nanoseconds to several microseconds. In fluid solutions the intensity of delayed excimer fluorescence (def) increases with time following excitation and goes through a maximum at a delay time near 300 ns. A kinetic model describing the formation and decay of the various triplet species is proposed, which reproduces the experimental observations using the rate constant for trapping of mobile triplet excitons as a fitting parameter. The best fit yields a minimum value for the trapping rate constant of 2.0 {times} 10{sup 9} M{sup {minus}1}s{sup {minus}1}, assuming every chromophore is a potential trap site. When transient triplet-triplet absorption methods are used, the second-order rate constant for the triplet-triplet annihilation (TTA) in fluid solution is found to be 2.5{times}10{sup 8} M{sup {minus}1}s{sup {minus}1}. Solid films at 10 K also show a maximum in the intensity of def recorded as a function of time. For solid films a best fit to the experimental results is achieved with a trapping rate constant of 8{times}10{sup 5}M{sup {minus}1}s{sup {minus}1}. This rate constant is similar to that recently determined for triplet quenching in copolymers containing the carbazolyl group and is probably controlled by the rate of energy migration.

• DOE Contract Number: FG08-84ER45107
• OSTI ID: 7109807
• Journal Information: Macromolecules; (United States), Vol. 23:1; ISSN 0024-9297
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBAZOLES
FLUORESCENCE SPECTROSCOPY
ABSORPTION SPECTROSCOPY
ENERGY LEVELS
ENERGY TRANSFER
EXPERIMENTAL DATA
FILMS
KINETICS
MATHEMATICAL MODELS
SOLUTIONS
TIME RESOLUTION
TRAPPING
AROMATICS
AZAARENES
AZOLES
DATA
DISPERSIONS
EMISSION SPECTROSCOPY
HETEROCYCLIC COMPOUNDS
INFORMATION
MIXTURES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
RESOLUTION
SPECTROSCOPY
TIMING PROPERTIES
400500* - Photochemistry