Additives and iodine (I2) are used to modify the binary room temperature ionic liquid (RTIL) electrolyte to enhance the photovoltaic performance of dye-sensitized solar cells (DSSCs). The short-circuit current density (JSC) of 17.89 mA/ cm₂, open circuit voltage (VOC) of 0.71 V and fill factor (FF) of 0.50 are achieved in the optimal device. An average photoelectric conversion efficiency (PCE) of 6.35% is achieved by optimization, which is over two times larger than that of the parent device before optimization (2.06%), while the maximum PCE can reach up to 6.63%.