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

Journal Article · Mon Jan 01 04:00:00 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), Journal Name: Macromolecules; (United States) Vol. 23:1; ISSN 0024-9297; ISSN MAMOB
• Country of Publication: United States
• Language: English

Related Subjects

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