In the present study, we propose low porosity and short length of TiO2 nanotubes (NTs) as underlayer in dye-sensitized solar cells (DSSCs). Photovoltaic characteristics of DSSCs with and without TiO2 NT underlayer are compared using various electrochemical analyses. Low porosity by small pore diameter, thick walled NT geometry and short length of NT underlayer help efficient charge transfer and reduced recombination at the interface of TiO2 nanoparticles (NPs)/Ti substrate. As a result, we can achieve a conversion efficiency of 6.89% for DSSCs with TiO2 NT underlayer, which is about 20% higher than that obtained from DSSCs with only a TiO2 NPs layer. (C) 2014 Elsevier Ltd. All rights reserved.