Determination of triplet quantum yields from triplet-triplet annihilation fluorescence

A new method for measuring triplet quantum yields is described and demonstr ated. In this self-calibrated technique, one compares intensities of prompt fluorescence and delayed triplet-triplet annihilation fluorescence from th e solution-phase sample of interest. This approach differs from other metho ds in that it requires no reference compounds, energy-transfer partners, or absolute measurements of triplet state energy, sample concentration, optic al density, excitation energy, or emission intensity. Instead, the triplet quantum yield is determined from the emission time profile, using data from a single sample. Results from this method agree with published values to w ithin ca; 0.02, even in the unfavorable case of a weakly fluorescent sample .