Novel organic sensitizers containing a bulky spirobifluorene unit for solar cell

Abstract

Three organic sensitizers JK-87, JK-88, and JK-89 containing a bulky spirobifluorene unit in the bridged group are designed and synthesized. Under standard global A.M. 1.5 solar condition, the JK-89 sensitized cell gave a short-circuit photocurrent density (J(sc)) of 13.02 mA cm(-2), an open-circuit voltage (V-oc) of 0.75 V, and a fill factor of 0.70, corresponding to an overall conversion efficiency 77 of 6.83%. The eta of JK-89 is higher than those of other two cells due to the larger J(sc). The improved J(sc) value is mainly attributed to the broad and red-shifted absorption band. (C) 2009 Elsevier Ltd. All rights reserved.