Depleted-heterojunction colloidal quantum dot photovoltaics employing low-cost electrical contacts

With an aim to reduce the cost of depleted-heterojunction colloidal quantum dot solar cells, we describe herein a strategy that replaces costly Au with a low-cost Ni-based Ohmic contact. The resultant devices achieve 3.5% Air Mass 1.5 power conversion efficiency. Only by incorporating a 1.2-nm-thick LiF layer between the PbS quantum dot film and Ni, we were able to prevent undesired reactions and degradation at the metal-semiconductor interface. (C) 2010 American Institute of Physics. [doi:10.1063/1.3463037]