Novel silicon phthalocyanine photosensitizers containing carboxylic acid based axial anchoring groups: Electrochemistry, spectroelectrochemistry, and dye sensitized solar cell performance

Abstract

In this study, two novel silicon phthalocyanines (SiPc) having axial anchoring groups (3: SiPc carrying bis-dibutyl phenoxy acrylic acid and 5: SiPc carrying bis-dibutyl phenoxy carboxylic acid) are synthesized as the photosensitizers of dye sensitized solar cells (DSSCs). The obtained novel photosensitizers are elucidated by using 1H NMR, MALDI-TOF, FT-IR, UV-Vis spectroscopy, and elemental analysis. Moreover, the electrochemistry of SiPcs is investigated with voltametric and in-situ spectroelectrochemical analysis. Both SiPcs illustrate similar two reductions and one oxidation Pc based redox processes. In-situ spectroelectrochemical results support the Pc based characters of the voltametric responses. The chromaticity diagrams and optical responses of the anionic and cationic moieties are recorded with the in-situ spectroelectrochemistry to determine the viability of them for various photoelectrochemical usage. Finally, SiPcs are investigated as dyes in DSSCs in order to investigate the influence of bis-dibutyl phenoxy acrylic acid and bis-dibutyl phenoxy carboxylic acid anchoring groups to the photovoltaic performance of SiPcs. DSSCs sensitized with SiPc (3) and SiPc (5) illustrate good photovoltaic performance with 1.48 and 1.99 mA/cm2 short circuit current density, 0.751 and 0.657 V open circuit potential, 0.52 and 0.57 fill factor, and 0.57% and 0.75% power conversion efficiency respectively.