Enhanced performance of a nanocrystalline dye-sensitized solar cell based on polyurethane dendrimers

Abstract

The use of novel p-chlorophenyl and styrenyl-TEMPO terminated fourth generation (G4) polyurethane dendrimers doped with KI and I₂ in conjunction with N3 dye as an efficient polymer electrolyte to improve the efficiency of nanocrystalline TiO₂ dye-sensitized solar cell (DSSC) is described. Coordinative interactions and structural changes of these dendritic polymer electrolytes have been characterized by X-ray diffraction (XRD), electrical conductivity and scanning electron microscopic (SEM) studies. The XRD and SEM results confirm the amorphous structure of the electrolytes. The ionic conductivity of doped polyurethane dendrimers was remarkably high and the values were in the range of 1.5 × 10⁻³ Scm⁻¹ to 1.1 × 10⁻³ Scm⁻¹ at room temperature. As a consequence, the performance of the devices fabricated with dendrimers were appreciably good compared to that fabricated without dendrimers and in one case the photocurrent, photovoltage, fill factor and energy conversion efficiency achieved were 10.6 mA cm⁻², 900 (mV), 0.51 and 8.5%, respectively, under simulated sunlight with AM 1.5 at 50 mW cm⁻².