title: Organic-inorganic halide perovskite/crystalline silicon four-terminal tandem solar cells.
abstract: Tandem solar cells constructed from a crystalline silicon (c-Si) bottom cell and a low-cost top cell offer a promising way to ensure long-term price reductions of photovoltaic modules. We present a four-terminal tandem solar cell consisting of a methyl ammonium lead triiodide (CH3NH3PbI3) top cell and a c-Si heterojunction bottom cell. The CH3NH3PbI3 top cell exhibits broad-band transparency owing to its design free of metallic components and yields a transmittance of >55% in the near-infrared spectral region. This allows the generation of a short-circuit current density of 13.7 mA cm(-2) in the bottom cell. The four-terminal tandem solar cell yields an efficiency of 13.4% (top cell: 6.2%, bottom cell: 7.2%), which is a gain of 1.8%abs with respect to the reference single-junction CH3NH3PbI3 solar cell with metal back contact. We employ the four-terminal tandem solar cell for a detailed investigation of the optical losses and to derive guidelines for further efficiency improvements. Based on a power loss analysis, we estimate that tandem efficiencies of ∼28% are attainable using an optically optimized system based on current technology, whereas a fully optimized, ultimate device with matched current could yield up to 31.6%.
authors.affiliation: École Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory, Rue de la Maladière 71b, 2002 Neuchâtel, Switzerland. philipp.loeper@epfl.ch.
authors.forename: Philipp
authors.initials: P
authors.lastname: Löper
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Moon
authors.forename: Sílvia Martín
authors.initials: SM
authors.lastname: de Nicolas
authors.forename: Bjoern
authors.initials: B
authors.lastname: Niesen
authors.forename: Martin
authors.initials: M
authors.lastname: Ledinsky
authors.forename: Sylvain
authors.initials: S
authors.lastname: Nicolay
authors.forename: Julien
authors.initials: J
authors.lastname: Bailat
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Yum
authors.forename: Stefaan
authors.initials: S
authors.lastname: De Wolf
authors.forename: Christophe
authors.initials: C
authors.lastname: Ballif