Improving the Efficiency of Dye-Sensitized Solar Cells via the Impact of Triphenylamine-Based Inventive Organic Additives on Biodegradable Cellulose Polymer Gel Electrolytes

Dye-sensitized solar cells based on biopolymer gel electrolyte systems deal with the perspective of good power conversion efficiency with low-cost fabrication. In this work, we synthesized an electron-rich triphenylamine core as an organic additive for hydroxyethyl cellulose (HEC) polymer gel electrolytes with a redox couple (I–/I3–), which is efficient for DSSCs. The presence of a more conjugated system and heteroatoms in additives paved the way for the whole mobility transport and quasi-Fermi level shift, which reduces the recombination reaction between the TiO2 surface and I3– ion, enhancing the organic photovoltaic properties. The electrochemical and photovoltaic properties of HEC gel electrolytes without additives (bare HEC) and with an additive ( 4-(di(1H-pyrrol-2-yl)methyl)-N,N-diphenylaniline (DPMDA), (1H-phenanthro[9,10-d]imidazol-2-yl)-N,N-diphenylaniline (PIDA), 4-(di(1H-pyrrol-2-yl)methyl)-N-(4-(di(1H-pyrrol-2-yl)methyl)phenyl)-N-phenylaniline (DPMPPA), N-(4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)-4-(1H-phenanthro[9,10-d]imidazol-2-yl)-N-phenylaniline (DPIPA), tris(4-(di(1H-pyrrol-2-yl)methyl)phenyl)amine (TDPMPA), and tris(4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)amine (TPIPA)) were studied, respectively; one of the organic additive tris(4-(1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)amine [TPIPA]-based polymer gel electrolytes (A6: TiO2/N3 dye/HEC/I–/I3–/TPIPA/Pt) showed good electrochemical properties, longer electron lifetime, and hence an improved photoconversion efficiency of 5.72% with better stability under light illumination of 100 mW/cm2.