Photovoltaic performances and lifetime analysis of TiO2/rGO DSSCs sensitized with Roselle and N719 dyes

Two titanium dioxide/reduced graphene oxide (TiO2/rGO) based dye-sensitized solar cells (DSSCs) were fabricated and separately sensitized with natural dye extracted from Roselle flowers and ruthenium-based dye of N719. The current-voltage (I-V) performances were measured using Visiontec Solar I-V tester at standard illumination of AM1.5 and irradiance level of 100 mW/cm 2 . The lifetime of the TiO2/rGO based DSSCs were furtherly investigated by measuring the I-V performances of the cells on the 5 th day and 15 th day. The highest power conversion efficiency (PCE) of 1.233 % was measured for the photoanode sensitized with N719 dye on the 15 th day. The PCE of Roselle dye dropped from 0.992 % on the 5 th day to 0.897 % on the 15 th day. Dye degradation and low electron injection have influenced the unstable photovoltaic performances of Roselle dye even with the presence of electron conducting path provided by the rGO particles.