Electron Beam Evaporated TiO2 Layer for High Efficiency Planar Perovskite Solar Cells on Flexible Polyethylene Terephthalate Substrates

Weiming Qiu, Ulrich W Paetzold, Robert Gehlhaar, Vladimir Smirnov, Hans-Gerd Boyen, Jeffrey Gerhart Tait, Bert Conings, Weimin Zhang, Christian Nielsen, Iain McCulloch, Ludo Froyen, Paul Heremans, David Cheyns

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110 Scopus citations


The TiO2 layer made by electron beam (e-beam) induced evaporation is demonstrated as electron transport layer (ETL) in high efficiency planar junction perovskite solar cells. The temperature of the substrate and the thickness of the TiO2 layer can be easily controlled with this e-beam induced evaporation method, which enables the usage of different types of substrates. Here, Perovskite solar cells based on CH3NH3PbI3-xClx achieve power conversion efficiencies of 14.6% on glass and 13.5% on flexible plastic substrates. The relationship between the TiO2 layer thickness and the perovskite morphology is studied with scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS). Our results indicate that pinholes in thin TiO2 layer lead to pinholes in the perovskite layer. By optimizing the TiO2 thickness, perovskite layers with substantially increased surface coverage and reduced pinhole areas are fabricated, increasing overall device performance.
Original languageEnglish (US)
Pages (from-to)22824-22829
Number of pages6
JournalJ. Mater. Chem. A
Issue number45
StatePublished - 2015

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