Suppressing charge recombination in disordered polymers blend medium

Abstract

Charge recombination is one of the critical factors that influence the performance of thin film polymer solar cells (TFPSC). In this investigation metal, plasmonic nano-particles are employed to suppress charge recombination and energy loss in TFPSC. Trimetallic nano-composite was successfully synthesized, composed of copper, nickel, and silver (Cu/Ni/Ag) using wet chemistry. The nano-composite was incorporated into polymer based solar absorber layers at different concentrations. The absorber layer is a fullerene-based bulk-heterojunction design using poly-3-hexylthiophene (P3HT) donor polymer. The results show that the power conversion efficiency (PCE) of the device doped with nano-composite has improved by 85% compared to the undoped one. The incorporation of tri-metallic nano-composite into the polymer blend solar absorber resulted in enhanced optical absorption and improved collection of photo-current as reflected by recorded high short circuit current density (Jsc) and fill factor (FF). The enhancement of the performance is due to the occurrence of local surface plasmon resonances in polymer medium. The experiment indicated that there is some increment in an open circuit voltage, which is attributed to the low energy losses as the result of improved exciton dissociation, charge carrier transport, and collection.