Highly efficient cross-linked PbS nanocrystal/$C60$ hybrid heterojunction photovoltaic cells

We present a highly efficient hybrid heterojunction photovoltaic (PV) cell with a colloidal inorganic nanocrystal (NC) electron donor and an organic electron acceptor. The heterojunction is formed by a thin film of cross-linked PbS NCs and a vacuum deposited $C60$ layer. Compared to the PbS-only PV cell, the heterojunction device has improved the power conversion efficiency from 1.6% to 2.2% under 1 sun of simulated Air Mass 1.5 Global (AM 1.5G) irradiation. The $C60$ layer effectively prevents exciton quenching at the NC/metal interface, as evidenced by a significant improvement in fill factor of the heterojunction devices.