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

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.