title: Nanoimprint-Transfer-Patterned Solids Enhance Light Absorption in Colloidal Quantum Dot Solar Cells.
abstract: Colloidal quantum dot (CQD) materials are of interest in thin-film solar cells due to their size-tunable bandgap and low-cost solution-processing. However, CQD solar cells suffer from inefficient charge extraction over the film thicknesses required for complete absorption of solar light. Here we show a new strategy to enhance light absorption in CQD solar cells by nanostructuring the CQD film itself at the back interface. We use two-dimensional finite-difference time-domain (FDTD) simulations to study quantitatively the light absorption enhancement in nanostructured back interfaces in CQD solar cells. We implement this experimentally by demonstrating a nanoimprint-transfer-patterning (NTP) process for the fabrication of nanostructured CQD solids with highly ordered patterns. We show that this approach enables a boost in the power conversion efficiency in CQD solar cells primarily due to an increase in short-circuit current density as a result of enhanced absorption through light-trapping.
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Younghoon
authors.identifier: 0000-0003-0860-2156
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Kristopher
authors.identifier: 0000-0002-3020-4093
authors.initials: K
authors.lastname: Bicanic
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Hairen
authors.identifier: 0000-0003-0821-476X
authors.initials: H
authors.lastname: Tan
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Olivier
authors.identifier: 0000-0001-5708-5058
authors.initials: O
authors.lastname: Ouellette
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Brandon R
authors.initials: BR
authors.lastname: Sutherland
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: F Pelayo
authors.initials: FP
authors.lastname: García de Arquer
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Jea Woong
authors.initials: JW
authors.lastname: Jo
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Mengxia
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Bin
authors.initials: B
authors.lastname: Sun
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Sjoerd
authors.initials: S
authors.lastname: Hoogland
authors.affiliation: Department of Electrical and Computer Engineering, University of Toronto , 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
authors.forename: Edward H
authors.initials: EH
authors.lastname: Sargent
keywords: Colloidal quantum dots; light trapping; nanostructured quantum dot solids; photovoltaics