title: Interface and Composition Analysis on Perovskite Solar Cells.
abstract: Organometal halide (hybrid) perovskite solar cells have been fabricated following four different deposition procedures and investigated in order to find correlations between the solar cell characteristics/performance and their structure and composition as determined by combining depth-resolved imaging with time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), and analytical scanning transmission electron microscopy (STEM). The interface quality is found to be strongly affected by the perovskite deposition procedure, and in particular from the environment where the conversion of the starting precursors into the final perovskite is performed (air, nitrogen, or vacuum). The conversion efficiency of the precursors into the hybrid perovskite layer is compared between the different solar cells by looking at the ToF-SIMS intensities of the characteristic molecular fragments from the perovskite and the precursor materials. Energy dispersive X-ray spectroscopy in the STEM confirms the macroscopic ToF-SIMS findings and allows elemental mapping with nanometer resolution. Clear evidence for iodine diffusion has been observed and related to the fabrication procedure.
authors.affiliation: C.H.O.S.E. (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome "Tor Vergata" , via del Politecnico 1, Rome 00133, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Matteocci
authors.affiliation: Research Center in the Physics of Matter and Radiation (PMR), Laboratoire Interdisciplinaire de Spectroscopie Electronique (LISE), University of Namur , B-5000 Namur, Belgium.
authors.forename: Yan
authors.initials: Y
authors.lastname: Busby
authors.affiliation: Research Center in the Physics of Matter and Radiation (PMR), Laboratoire Interdisciplinaire de Spectroscopie Electronique (LISE), University of Namur , B-5000 Namur, Belgium.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Pireaux
authors.affiliation: Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage road, CB3 0FS, Cambridge, U.K.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Divitini
authors.affiliation: Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage road, CB3 0FS, Cambridge, U.K.
authors.forename: Stefania
authors.initials: S
authors.lastname: Cacovich
authors.affiliation: Department of Materials Science & Metallurgy, University of Cambridge , 27 Charles Babbage road, CB3 0FS, Cambridge, U.K.
authors.forename: Caterina
authors.initials: C
authors.lastname: Ducati
authors.affiliation: C.H.O.S.E. (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome "Tor Vergata" , via del Politecnico 1, Rome 00133, Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Di Carlo
keywords: EDX-STEM; ToF-SIMS; XPS; filaments; perovskite solar cells