title: Solar cells based on inks of n-type colloidal quantum dots.
abstract: New inorganic ligands including halide anions have significantly accelerated progress in colloidal quantum dot (CQD) photovoltaics in recent years. All such device reports to date have relied on halide treatment during solid-state ligand exchanges or on co-treatment of long-aliphatic-ligand-capped nanoparticles in the solution phase. Here we report solar cells based on a colloidal quantum dot ink that is capped using halide-based ligands alone. By judicious choice of solvents and ligands, we developed a CQD ink from which a homogeneous and thick colloidal quantum dot solid is applied in a single step. The resultant films display an n-type character, making it suitable as a key component in a solar-converting device. We demonstrate two types of quantum junction devices that exploit these iodide-ligand-based inks. We achieve solar power conversion efficiencies of 6% using this class of colloids.
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Ning
authors.forename: Haopeng
authors.initials: H
authors.lastname: Dong
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhang
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Voznyy
authors.forename: Edward H
authors.initials: EH
authors.lastname: Sargent
keywords: halide ligands; n-type; nanocrystals; photodiode; solar cells