title: Advanced Architecture for Colloidal PbS Quantum Dot Solar Cells Exploiting a CdSe Quantum Dot Buffer Layer.
abstract: Advanced architectures are required to further improve the performance of colloidal PbS heterojunction quantum dot solar cells. Here, we introduce a CdI2-treated CdSe quantum dot buffer layer at the junction between ZnO nanoparticles and PbS quantum dots in the solar cells. We exploit the surface- and size-tunable electronic properties of the CdSe quantum dots to optimize its carrier concentration and energy band alignment in the heterojunction. We combine optical, electrical, and analytical measurements to show that the CdSe quantum dot buffer layer suppresses interface recombination and contributes additional photogenerated carriers, increasing the open-circuit voltage and short-circuit current of PbS quantum dot solar cells, leading to a 25% increase in solar power conversion efficiency.
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Tianshuo
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Earl D
authors.initials: ED
authors.lastname: Goodwin
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Jiacen
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Han
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Diroll
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Murray
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical and Systems Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Cherie R
authors.initials: CR
authors.lastname: Kagan
keywords: CdSe; PbS; buffer layer; interface; quantum dot; solar cell