Quenching of excited states at the interface, molecular crystal/electrolyte

The wavelength dependence of the fluorescence yield and of the photocurrent for anthracene crystals in contact with an electrolyte solution has been measured. A correlation between the fluorescence yield and the quantum efficiency of charge carrier generation at the contact has been derived which provides a means for determination of the contribution of the charge and energy transfer to the fluorescence quenching process. Experiments with a solution of Na2IrCl6 in 0.5 N HCl showed that for this system quenching of the fluorescence occurs predominantly by energy transfer with a small contribution of charge transfer.