title: Ambient-processed colloidal quantum dot solar cells via individual pre-encapsulation of nanoparticles.
abstract: We report colloidal quantum dot solar cells fabricated under ambient atmosphere with an active area of 2.9 mm(2) that exhibit 3.6% solar power conversion efficiency. The devices are based on PbS tuned via the quantum size effect to have a first excitonic peak at 950 nm. Because the formation of native oxides and sulfates on PbS leads to p-type doping and deep trap formation and because such dopants and traps dramatically influence device performance, prior reports of colloidal quantum dot solar cells have insisted on processing under an inert atmosphere. Here we report a novel ligand strategy in which we first encapsulate the quantum dots in the solution phase with the aid of a strongly bound N-2,4,6-trimethylphenyl-N-methyldithiocarbamate ligand. This allows us to carry out film formation and all subsequent device fabrication under an air atmosphere.
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Ratan
authors.initials: R
authors.lastname: Debnath
authors.forename: Jiang
authors.initials: J
authors.lastname: Tang
authors.forename: D Aaron
authors.initials: DA
authors.lastname: Barkhouse
authors.forename: Xihua
authors.initials: X
authors.lastname: Wang
authors.forename: Andras G
authors.initials: AG
authors.lastname: Pattantyus-Abraham
authors.forename: Lukasz
authors.initials: L
authors.lastname: Brzozowski
authors.forename: Larissa
authors.initials: L
authors.lastname: Levina
authors.forename: Edward H
authors.initials: EH
authors.lastname: Sargent