<![CDATA[This present study investigates the effect of pH variation (2-12) on anthocyanin extraction from Clitoria ternatea L. and polyetherimide (PEI) polymer membrane electrolyte performance in dye-sensitized solar cells (DSSCs). The extraction of anthocyanin was conducted through the utilization of microwave-assisted extraction (MAE) at 280 watts for 15 minutes, employing a distilled water ratio of 1:20 ratio. This was followed by a systematic pH conditioning procedure. The characterization employed a range of analytical techniques, including UV-Vis spectrophotometry (400-800 nm), FTIR (4000-500 cm-1), cyclic voltammetry for HOMO-LUMO analysis, SEM (1,000×-10,000× magnification), XRD for crystallinity determination, DSC for thermal stability (60-450°C), and electrochemical impedance spectroscopy. Results obtained demonstrated that pH 4 anthocyanin exhibited maximum dual absorption peaks at 571.21 nm and 612.85 nm, representing the magenta-colored quinoidal base structure with superior light-harvesting capabilities. The FTIR analysis confirmed the presence of stable functional groups, including O-H stretching (3338.08 cm-1), C=O stretching (1710 cm-1), and aromatic C=C (1416.91 cm-1) across all pH conditions without new chemical bond formation. The pH 4 dye demonstrated the narrowest energy bandgap (0.1316 eV) with HOMO at -4.1597 eV and LUMO at -4.0281 eV, optimally aligned with the TiO2 conduction band (-4.0 eV) for efficient electron injection. The PEI membrane exhibited asymmetric morphology with 12.77% crystallinity, a hierarchical porous structure, and excellent thermal stability up to 500°C. The performance of the DSCC reached its maximum at a pH of 4, with efficiency η = 2.37%, Voc = 597 mV, Jsc = 0.0119 mA/cm2, FF = 5.60%, and minimum charge transfer resistance Rct = 100–150 Ω. These findings demonstrate that pH 4 optimization is critical for enhancing the efficiency of DSSC through quinoidal base formation, enhanced molecular conjugation, and accelerated charge transfer processes in environmentally sustainable photovoltaic systems.]]>
