title: Reduced Carrier Recombination in PbS - CuInS2 Quantum Dot Solar Cells.
abstract: Energy loss due to carrier recombination is among the major factors limiting the performance of TiO2/PbS colloidal quantum dot (QD) heterojunction solar cells. In this work, enhanced photocurrent is achieved by incorporating another type of hole-transporting QDs, Zn-doped CuInS2 (Zn-CIS) QDs into the PbS QD matrix. Binary QD solar cells exhibit a reduced charge recombination associated with the spatial charge separation between these two types of QDs. A ~30% increase in short-circuit current density and a ~20% increase in power conversion efficiency are observed in binary QD solar cells compared to cells built from PbS QDs only. In agreement with the charge transfer process identified through ultrafast pump/probe spectroscopy between these two QD components, transient photovoltage characteristics of single-component and binary QDs solar cells reveal longer carrier recombination time constants associated with the incorporation of Zn-CIS QDs. This work presents a straightforward, solution-processed method based on the incorporation of another QDs in the PbS QD matrix to control the carrier dynamics in colloidal QD materials and enhance solar cell performance.
authors.affiliation: 1] LPEM, PSL Research University, ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France [2] CNRS, UMR 8213, F-75005 Paris, France [3] Sorbonne Universités, UPMC Univ Paris 06, F-75005 Paris, France.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Sun
authors.affiliation: 1] LPEM, PSL Research University, ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France [2] CNRS, UMR 8213, F-75005 Paris, France [3] Sorbonne Universités, UPMC Univ Paris 06, F-75005 Paris, France.
authors.forename: Gary
authors.initials: G
authors.lastname: Sitbon
authors.affiliation: 1] LPEM, PSL Research University, ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France [2] CNRS, UMR 8213, F-75005 Paris, France [3] Sorbonne Universités, UPMC Univ Paris 06, F-75005 Paris, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pons
authors.affiliation: FOM Institute AMOLF, Science Park 104, Amsterdam 1098 XG, The Netherlands.
authors.forename: Artem A
authors.initials: AA
authors.lastname: Bakulin
authors.affiliation: 1] LPEM, PSL Research University, ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France [2] CNRS, UMR 8213, F-75005 Paris, France [3] Sorbonne Universités, UPMC Univ Paris 06, F-75005 Paris, France.
authors.forename: Zhuoying
authors.initials: Z
authors.lastname: Chen