Donor—acceptor luminescent systems

Weller and Zachariasse thoroughly investigated exciplex formation and luminescence for donor acceptor systems in THF [18]. A particularly interesting result from their work came from an examination of the temperature dependence of radiative charge recombination between 9,10-dimethylanthracene anion (DMA") and TPTA+ in THF [19]. They found that both exciplex emission and fluorescence from DMA were observed in solution at low temperature (ca. —50°C). As the solution temperature is raised, the excimer emission decreases in relative intensity, and at room temperature the emission is nearly completely DMA fluorescence. The monomer-to-exciplex emission intensity ratio as a function of temperature follows Arrhenius kinetic behavior and yields an activation barrier that is nearly the same as the energy gap between the exciplex and the DMA states. Thus, their model consisted of reaction of the solvent-separated ions to form an intimate emissive ion pair which could dissociate to yield the singlet anthracene derivative. 

Aromatic systems have always attracted considerable attention. Eremenko et al. [107,108], choosing naphthalene and naphthylamine as probe molecules in alkah metal and alkaline earth ion-exchanged faujasites, investigated the formation of donor-acceptor complexes and the oxidation of naphthalene using luminescence and DR spectra. Naphthalene adsorbed from hexane solution in... 

A method for calculating the probability and efficiency of energy transfer between inorganic ions, which have well-defined electronic levels from donor and acceptor luminescence intensities, and for luminescent hfetime was proposed by Reisfeld et al. (71). Formulae were derived from rate equations applicable to a system consisting of a pair of rnilike rare earth ions in a glass medium. 

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