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Optical analysis of CH 3 NH 3 Sn x Pb 1−x I 3 absorbers: a roadmap for perovskite-on-perovskite tandem solar cells

2016; Royal Society of Chemistry; Volume: 4; Issue: 29 Linguagem: Inglês

10.1039/c6ta04840d

2050-7488

Miguel Anaya, Juan‐Pablo Correa‐Baena, Gabriel Lozano, Michael Saliba, Pablo Anguita, Bart Roose, Antonio Abate, Ullrich Steiner, Michaël Grätzel, Mauricio E. Calvo, Anders Hagfeldt, Hernán Míguez,

Chalcogenide Semiconductor Thin Films

Organic-inorganic perovskite structures in which lead is substituted by tin are exceptional candidates for broadband light absorption. Herein we present a thorough analysis of the optical properties of CH3NH3Sn x Pb1-x I3 films, providing the field with definitive insights about the possibilities of these materials for perovskite solar cells of superior efficiency. We report a user's guide based on the first set of optical constants obtained for a series of tin/lead perovskite films, which was only possible to measure due to the preparation of optical quality thin layers. According to the Shockley-Queisser theory, CH3NH3Sn x Pb1-x I3 compounds promise a substantial enhancement of both short circuit photocurrent and power conversion efficiency in single junction solar cells. Moreover, we propose a novel tandem architecture design in which both top and bottom cells are made of perovskite absorbers. Our calculations indicate that such perovskite-on-perovskite tandem devices could reach efficiencies over 35%. Our analysis serves to establish the first roadmap for this type of cells based on actual optical characterization data. We foresee that this study will encourage the research on novel near-infrared perovskite materials for photovoltaic applications, which may have implications in the rapidly emerging field of tandem devices.