In this research, the dye-sensitized solar cells (DSSCs) were fabricated by using g-C3N4 and ZnO modified TiO2 nanotube (TNT) arrays as photoanodes. The TNT arrays were synthesized by the anodizing method. G-C3N4 and ZnO modified TNTs were synthesized via a solvothermal method in which ethylene glycol served as a solvent. The short circuit current (I-SC) and open-circuit voltage (V-OC) of DSSCs based on ZnO g-C3N4 modified TNTs photoanode considerably increased from 9.25 mA/cm(-2) to 14.68 mA/cm(-2), and from 0.707 mV to 0.695 mV, respectively, resulting in a135% increase in the efficiency compared with the pure TNT arrays photoanode. However, the DSSC fabricated with g-C3N4 TNT did not show much improvement in the conversion efficiency compared with the pure TNT arrays photoanode, implying more effective processes of the carrier production and transport between ZnO, g-C3N4 and TNTs. Also, the electrochemical impedance spectroscopy (EIS) and open-circuit voltage decay (OCVD) analyses showed that ZnO g-C3N4 can promote the electron collecting rate, suppress he electron recombination and extend the electron lifetime. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.