Studies of solar effect of safranine, methylene blue and Azur-B with reductants and their photogalvanic effect

Department of Chemistry, Jai Narain Vyas University, Jodhpur-342 005, Rajasthan, India E.mail : rcmeena007 @rediffmail.com Manuscript received 23 July 2007, revised 5 December 2007, accepted 5 December 2007 Photochemical studies of dyes has contributed to the understanding of the mechanism of electron transfer reactions in photoelectro-chemical devices1-6. A umber of photoinduced redox reactions have been studied. These reactions prove to be helpful in electrochemical cell for the conversion of solar energy to electrical energy by chemical means7-9. It has been found that phenazyne dyes in conjunction with different reducing agents is efficient photosensitizers for probing charge transfer in photochemical cells1-8. Studies carried out by Isabel et al.9 on the photo redox reactions of thionine with iron(ll), cobalt(II) and manganese(II) by flash photolysis techniques provided better understanding of the mechanism of thionine based photogalvanic cell. A detailed literature survey1-23 reveals that different photosensitizers mainly cationic and neutral dyes and reductants have been used in photogalvanic cells hut the use of combination of anionic, cations and neutral dyes as photosensitizcrs in the photogalvanic cell for solar energy conversion and storage is rare, and hence the present work is undertaken. The system consisting of anionic dye safranine in aqueous solution generates pholovoltage when studied in photogalvanic cell. The open circuit photovoltage, the short circuit current and solar energy efficiency of these systems have been determined. The effect of different parameters on electrical output of the cell were observed and a mechanism has also been proposed for the generation of photocurrent in photogalvanic cell