Enhancing Performance of CdS Quantum Dot-Sensitized Solar Cells by Two-Dimensional g-C3N4 Modified TiO2 Nanorods

In present work, two-dimensional g-C 3 N 4 was used to modify TiO 2 nanorod array photoanodes for CdS quantum dot-sensitized solar cells (QDSSCs), and the improved cell performances were reported. Single crystal TiO 2 nanorods are prepared by hydrothermal method on transparent conductive glass and spin-coated with g-C 3 N 4 . CdS quantum dots were deposited on the g-C 3 N 4 modified TiO 2 photoanodes via successive ionic layer adsorption and reaction method. Compared with pure TiO 2 nanorod array photoanodes, the g-C 3 N 4 modified photoanodes showed an obvious improvement in cell performances, and a champion efficiency of 2.31 % with open circuit voltage of 0.66 V, short circuit current density of 7.13 mA/cm 2 , and fill factor (FF) of 0.49 was achieved, giving 23 % enhancement in cell efficiency. The improved performances were due to the matching conduction bands and valence bands of g-C 3 N 4 and TiO 2 , which greatly enhanced the separation and transfer of the photogenerated electrons and holes and effectively suppressed interfacial recombination. Present work provides a new direction for improving performance of QDSSCs.