Dual Functional TiO₂–Au Nanocomposite Material for Solid-State Dye-Sensitized Solar Cells

Titanium dioxide-gold nanocomposite ((TiO₂–Au)_nps) materials dispersed in poly(diallyldimethylammonium chloride) (PDDA) polymer electrolyte are employed as solid-state electrolytes in a dyesensitized solar cell (DSSC) containing nanocrystalline TiO₂ nanoparticle (P25) or (P25–Au)_nps thin film photoanode adsorbed with a near–IR dye sensitizer, nickel–phthalocyanine (NiPcTs). The photocurrent–photovoltage characteristics of the DSSCs are evaluated under standard AM 1.5 G simulated solar irradiation of 100 mW/cm2. The (TiO₂–Au)_nps nanocomposite material incorporated into the PDDA polymer electrolyte promotes interfacial charge transfer process, reduces crystallinity of the polymer electrolyte and enhances mobility of the I ^–/I ^– ₃ redox couple, which are resulted in ∼6-fold increase in the overall solar to electrical energy conversion efficiency when compared to the unmodified polymer electrolyte based DSSC. When the P25 photoanode is replaced with the (P25–Au)_nps photoanode, a further 8-fold increase in the overall energy conversion efficiency is achieved, owing to the increas in the charge transport through the photoanode. The photovoltaic performance of the present DSSC configuration is also compared with that of a cell sensitized by using standard N719 dye.