ESTIMATION OF TRIPLET ENERGIES FROM ELECTROGENERATED CHEMI-LUMINESCENCE - POSSIBILITIES AND RESTRICTIONS

The advantages and disadvantages of electrogenerated chemiluminescence (ECL) as a method for estimating triplet energies ET of organic compounds are demonstrated in several examples involving strong, weak or non-luminescent compounds. It is shown that in many cases ET can be determined within an error of ±0.1 eV from the thermodynamic relationships between electrochemical and spectroscopic data, from ECL quenching or from sensitized ECL. The method can also be successfully applied to substances in which phosphorescence and delayed fluorescence investigations have failed. It was found that formation of exciplexes and irreversible reactions of the ion radicals may lead to misinterpretation of the results. In such cases, additional measurements were carried out to confirm the interpretation of the triplet mechanism and to rule out chemical complications. © 1979.