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 AM 1.5 solar condition, the JK-89 sensitized cell gave a short-circuit photocurrent density (Jsc) of 13.02 mAcm− 2, an open-circuit voltage (Voc) of 0.75 V, and a fill factor of 0.70, corresponding to an overall conversion efficiency η of 6.83%. The η of JK-89 is higher than those of other ...
