PHOTOVOLTAIC AND PHOTOELECTRIC PROPERTIES OF AL MIXED MONOLAYERS OF CHL A-SQDG/AG SANDWICH CELLS/

With a view to examining the effect of the lipid sulphoquinovosyldiacy lglycerol (SQDG) on the photovoltaic and photoelectric properties of c hlorophyll a (Chl a) sandwich cells of the type Al/mixed monolayers of Chl a-SQDG/Ag have been fabricated. Various photovoltaic parameters o f the cells, i.e. short-circuit photocurrent, open-circuit photovoltag e, fill factor and power conversion efficiency, have been measured at 672 nm (the maximum of Chl a absorption in the red region). For an inc ident light power of 21 muW cm-2 these parameters are 20 nA cm-2 450 m V, 0.27 and 0.02% respectively for cells of Chl a-SQDG in a 1:0.025 mo lar ratio, while for cells of Chl a-SQDG in a 1:0.25 molar ratio they are 18 nA cm-2, 40 mV, 0.26 and 0.002% respectively. This indicates th at the introduction of an increased quantity of SQDG in Chl a decrease s the cell efficiency. This is possibly due to the intervening effect of SQDG which makes the transport of photogenerated charge carriers (i n Chl a) across the multilayers of Chl a-SQDG and to the electrodes ra ther difficult. The introduction of recombination sites by SQDG as see n from the lower values of gamma (about 0.7) may also be a reason for the lower efficiency of cells with increased quantities of SQDG.