delayed fluorescence

Also contains definition of: recombination fluorescence
https://doi.org/10.1351/goldbook.D01579
Three types of delayed
fluorescence
are known:
  1. E-type delayed
    fluorescence
    : The process in which the first excited
    singlet state
    becomes populated by a thermally activated
    radiationless transition
    from the first excited
    triplet state
    . Since in this case the populations of the singlet and triplet states are in thermal equilibrium, the lifetimes of delayed
    fluorescence
    and the concomitant
    phosphorescence
    are equal.
  2. P-type delayed
    fluorescence
    : The process in which the first excited
    singlet state
    is populated by interaction of two molecules in the
    triplet state
    (triplet-triplet
    annihilation
    ) thus producing one molecule in the excited
    singlet state
    . In this
    biphotonic process
    the
    lifetime
    of delayed
    fluorescence
    is half the value of the concomitant
    phosphorescence
    .
  3. Recombination fluorescence: The first excited
    singlet state
    becomes populated by recombination of
    radical ions
    with electrons or by recombination of radical ions of opposite charge.
See also:
delayed luminescence
Source:
PAC, 1984, 56, 231. (Nomenclature, symbols, units and their usage in spectrochemical analysis-Part VI: molecular luminescence spectroscopy) on page 233 [Terms] [Paper]
See also:
Orange Book, 2nd ed., p. 185 [Terms] [Book]
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2235 [Terms] [Paper]