delayed luminescence
luminescence decaying more slowly than that expected from the rate of decay of the emitting state. The following mechanisms of luminescence provide examples:
  1. triplet-triplet or singlet-singlet annihilation to form one molecular entity in its excited singlet state and another molecular entity in its electronic ground state (sometime referred to as P type),
  2. thermally activated delayed fluorescence involving reversible intersystem crossing (sometimes referred to as E type), and
  3. combination of oppositely charged ions or of an electron and a cation. For emission to be referred to in this case as delayed luminescence at least one of the two reaction partners must be generated in a photochemical process.
See also: delayed fluorescence
PAC, 1988, 60, 1055. 'Glossary of terms used in photochemistry (Recommendations 1988)' on page 1065 (
See also:
Orange Book, 2nd ed., p. 185 (