Photovoltaic Effect of Acriflavine in Collodion Film

cesses in photochemical behaviours o f the dye. Th e observed photopotential in aqueous acriflavine solution is positive or negative against the dark electrode, depending on pH . The positive sign implys that the photoreduction of dye is more predominant than the photooxidation. The negative sign is obtained when the photooxidation is the predominant reaction. Using the electrode coated directly or ind irectly w ith a very thin film o f acriflavine-dispersed collodion, the contributions from photo-reduction and -oxidation to the photopotential were sepa­ rated. The spectral sensitivity o f photopotentials gives us an useful information about the oxidationreduction mechanism o f bound dyes. Th e photo-ejection o f an electron from the excited singlet state of dye molecule, which was considered by L i m and o thers1 to be responsible for the de­ layed fluorescence o f acriflavine in r ig id media, seems to be favourable for understanding o f photo­ potential properties at shorter wavelengths o f excitation.