Photovoltaic Devices with a Low Band Gap Polymer and CdSe Nanostructures Exceeding 3% Efficiency

Abstract

We report the fabrication and measurement of solar cells approaching a power conversion efficiency of 3.2% using a low band gap conjugated polymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] and CdSe nanoparticles. These devices exhibit an external quantum efficiency (EQE) of >30% in a broad range of 350−800 nm with a maximum EQE of 55% in a range of 630−720 nm. We also present certified device efficiencies of 3.13% under AM 1.5 illumination.