Quenching of excited anthracene, pyrene, and perylene by diphenyliodonium salts is studied using steady- and transient state spectroscopy methods. The photoinduced electron-transfer rate constants were determine by Stern-Volmer anal. These values show that Ph2I+AsF6- is the most efficient quencher and that the quenching processes are near diffusion-controlled. Comparing the quenching constants obtained by intensity measurement with that obtained by lifetime measurement, it is confirmed that the quenching dynamic, and no charge transfer complex is formed in ground state between the fluorophore and the onium salt.

Key words: ANTHRACENE, SENSITIZATION, LIGHT DEGRADATION, PYRENE