460501 Metal Oxide Electron-Selective Layers for Inverted Perovskite Solar Cells By Atomic Layer Deposition

Monday, November 14, 2016: 8:32 AM
Golden Gate 5 (Hilton San Francisco Union Square)
Axel Palmstrom1, Kevin Bush2, Michael McGehee2 and Stacey F. Bent1, (1)Chemical Engineering, Stanford University, Stanford, CA, (2)Materials Science and Engineering, Stanford University, Stanford, CA

Perovskites are promising candidates for low cost, high efficiency light absorbers with a large, tunable band gap. Recent advances in photostability and thermal stability from the introduction of mixed-cation lead mixed-halide perovskites in the form of cesium formamidinium (CsFA) perovskites has lead to significant interest in the development of perovskite-silicon tandem solar cells. Improvements in the deposition of transparent contacts, stability of organics within the device structure and blocking of moisture to the perovskite absorber must be made to realize highly efficient and stable perovskite-silicon devices. The improved thermal stability of the CsFA perovskite has opened up new processing options through atomic layer deposition (ALD) for the conformal coating of metal oxide materials on top of perovskite absorbers. In this work, we explore TiOx and SnOx ALD thin films deposited on top of CsFA perovskite devices in an inverted structure as dual-purpose layers for electron-selectivity and degradation protection. We will discuss the effects of ALD processing conditions on TiOx and SnOx electronic properties as well as on CsFA perovskite stability. We achieve stable >15% power conversion efficiency with 1.6 eV perovskite devices through maximum power point tracking and demonstrate the effectiveness of ALD metal oxide layers as buffer layers for the sputtering of indium tin oxide contacts for semi-transparent devices with >14% efficiency.

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See more of this Session: Nanostructured/Thin Film Photovoltaics
See more of this Group/Topical: Materials Engineering and Sciences Division