Free-standing conical TiO2 nanotube arrays with various lengths were prepared directly on the Ti foil by adjusting the applied voltage during the two-step anodic oxidation process. Then the as-grown TiO2 nanotube arrays were transferred onto the flexible ITO/PEN substrates by using titania slurries without any organic binder, which were used as the photoanodes to fabricate the front-illuminated flexible DSSCs. SEM image showed that the conical TiO2 nanotube arrays were successfully obtained. UV-vis spectra were used to explore the enhanced optical absorption compared with the regular cylinder TiO2 nanotube arrays. The photovoltaic properties for incident photon to current efficiency (IPCE) and photovoltaic conversion efficiency was also studied under AM 1.5 illumination, which showed that the conical TiO2 nanotube arrays with 14 pm have the higher photovoltaic performance (3.78%) than that of the regular cylinder TiO2 nanotube arrays (2.79%). The reason of the enhanced photovoltaic performance is due to the enhanced light-harvesting ability of the conical TiO2 nanotube arrays. (C) 2014 Elsevier Ltd. All rights reserved.