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 of fluorescence and incident photon to current conversion efficiency (IPCE) as a function of applied bias suggest that the fluorescence quenching and the photocarrier generation are interrelated. Fluorescence quenching has thus been utilized to determine the photogeneration efficiency, 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 70%, 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 American Institute of Physics.