FLUORESCENCE AND PHOTOELECTROCHEMICAL BEHAVIOR OF CHLOROPHYLL-A ADSORBED ON A NANOCRYSTALLINE SNO2 FILM

Fluorescence and photoelectrochemical studies of chlorophyll a (Chi a) adsorbed on nanocrystalline SnO2 film were carried out. The results o f fluorescence and incident photon to current conversion efficiency (I PCE) as a function of applied bias suggest that the fluorescence quenc hing and the photocarrier generation are interrelated. Fluorescence qu enching has thus been utilized to determine the photogeneration effici ency, eta(e), of charges in a SnO/(2)Chl a based photoelectrochemical cell. A value of 0.75 was obtained for eta(e) for unbiased cells. With an IPCE of 13%, eta(e) of 75%, and a Light harvesting efficiency of 7 0%, the charge collection efficiency of similar to 23% was evaluated, These results suggest that the losses due to the charge recombination are a major factor that limit the efficiency of the cells. (C) 1996 Am erican Institute of Physics.