Dear All,
I look for nonlinear fluorescence phenomenon, other than that which
assumes classical two-photon excitation, which I plane to use in
confocal
fluorescence microscopy. One of candidates is p-type (pyrene-type)
delayed fluorescence. Does anyone can recommend me
a references on the subject or suggest me a  me a pair (donor-acceptor)
of dyes (fluorophores)  which can be used for efficient demonstration of

sensitized anti-Stokes p-type  delayed fluorescence by means of
triplet-triplet annihilation (selfquenching of molecules in triplet
state)? This should work in visible spectral region, fluid solution,
and room
temperature.
An (old) textbook example I have found is phenantrene-naphtalene pair
(N.J. Turro, Modern Molecular Photochemistry) which works in UV region
and no data about concentrations of donor and acceptor in solution are
available.

Marek Kowalczyk
Fac. Physics
Warsaw University
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