Effective and tunable light trapping in bulk heterojunction organic solar cells by employing Au-Ag alloy nanoparticles

Abstract

Effective and tunable light trapping in organic solar cells (OSCs) has been demonstrated by employing Au-Ag alloy nanoparticles (NPs). A simple vacuum thermal annealing method has been employed to fabricate the Au-Ag alloy NPs with tunable molar ratio, and thereafter tunable localized surface plasmon resonance (LSPR). The incorporation of the alloy NPs with an appropriate molar ratio into the OSCs structures supports amplification of the electric field near the particles surface through LSPR and results in an enhanced light absorption at the absorption wavelength region of the absorber owing to the near field coupling. The short-circuit photocurrent density of the alloy NPs-based OSCs is improved from 7.37 to 8.74 mA/cm2 compared to that of control OSCs, and the efficiency of 3.03% is obtained, which corresponds to an enhancement factor of 19%.