Dye-sensitized solar cells with efficiency enhancement surpassing 65% through layer-by-layer assembled plasmonic photoanodes

Even though plasmonic photoelectrodes have paved the way for high-efficiency DSSC, metal nanoparticle degradation in iodine-based electrolytes restricts commercialization. In order to protect the plasmonic nano-particles, the plasmonic photoelectrode having a layer-by-layer assembly of TiO2/Ag/TiO2 has been developed by a simple photoreduction at various time intervals followed by mild TiCl4 treatment over the TiO2 film and fabricated into dye-sensitized solar cells (DSSC). On evaluating the performance of fabricated DSSC under AM 1.5 G irradiation with the intensity of 100 mWcm(-2), the champion cell (eta = 11%) shows 65% enhancement in power conversion efficiency compared to the pristine TiO2 photoanode-based DSSC (eta = 6.67%). The photo-current density has been improved due to the surface plasmon resonance effect of Ag nanoparticles and the formation of TiO2 by TiCl4 treatment not only protects the Ag metal nanoparticles as well as creates more dye-loading sites. A negative shift in the Fermi-level caused by the accumulation of electrons in Ag, triggers the open-circuit voltage to increase by 100 mV which is evident from the Mott-Schottky analysis. The electron lifetime value is increased due to increased charge collection efficiency. The champion cell shows 91.5% retainment in efficiency even after 5 days.