Inhomogeneous electrochemiluminescence. I: Integral encounter theory of kinetics and yield

The maximal quantum yield of triplet luminescence found experimentally is sometimes less than 1, even when the excitation is the sole result of charge recombination. This phenomenon may be a result of the biexcitonic annihilation of triplets produced in a narrow strip at the border between the space separated anions and cations. The kinetics of this process is calculated and the maximal yield of fluorescence is shown to decrease with excitation life time and increase with triplet diffusion out of the strip. Alternatively, the maximal quantum yield may be reduced due to the trivial triplet quenching by neutral precursors of ions.