In contrast, the acidity has a significant effect on the HOMO and LUMO energy levels of the dyes, as shown in Table 2. Particularly, the LUMO energy level can influence the injection of electrons into the conduction band (CB) of TiO2[6]. Greater LUMO energy levels of the dye might increase the voltage difference between the dye and the electrolyte, facilitating the electron transfer between the dye and the TiO2. Nevertheless, the Jsc value of the N719 dye-based DSSC was three times higher than that of the PL dye-based DSSCs