Harvest of near infrared light in PbSe nanocrystal-polymer hybrid photovoltaic cells

We report a hybrid photovoltaic cell where PbSe nanocrystals were used to sensitize the conjugated polymer into the infrared. The device exhibited an incident monochromatic photon to current conversion efficiency of 1.3% at $\lambda =805\mathrm{nm}$ . Under 1 sun AM 1.5 illumination, the infrared response $(780\mathrm{nm}<\lambda <1600\mathrm{nm})$ of the embedded nanocrystals contributes to 33% of the overall photocurrent of the photovoltaic cell. The observed intensity dependences of the photocurrents have revealed the pseudomonomolecular recombination kinetics in the nanocrystal quantum dot polymer composite, indicating that the efficiency of the hybrid photovoltaic cells can be enhanced by reducing the potential barriers due to the ligand molecules at the surfaces of nanocrystals.