a high short-circuit photocurrent density of 9.3 mA cm2. The mentioned features have determined the 54% improved efficiency of SC-A with the bilayer ultrafine TiO2 combination (dice-like TiO2/P18). Therefore, the bilayer ultrafine TiO2 combination (dice-like TiO2/ P-18) is one of ideal ways to improve the performance of DSSCs.