Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Poster: Fundamentals of Perovskite Photovoltaics (joint session CPP, DS, HL)

CPP 13.26: Poster

Monday, March 20, 2017, 18:30–21:00, P1A

High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy on Lead Halide Perovskite Precursors — •Pascal Becker^1,2, Justus Just¹, Charles J. Hages¹, Oliver Müller², and Thomas Unold¹ — ¹Helmholtz-Zentrum Berlin für Materialien und Energie, Germany — ²Bergische Universität Wuppertal, Germany

Perovskites as photon absorbers in thin film solar cells have drawn immense attention resulting in a rapid rise in the achieved power conversion efficiencies exceeding 20 % within a few years. Despite the intensive research in this field little is known about the formation process of these perovskite thin films on an atomic level. X-Ray Absorption Spectroscopy (XAS) is a well suited method to investigate electronic and structural properties of thin film materials. Also, residual precursor phases can be identified by this method even when X-Ray Diffraction (XRD) fails to detect. By using high quality and high resolution reference spectra in a linear combination analysis the amount of these secondary phases can be quantified.

Therefore High Energy Resolution Fluorescence detected XAS (HERFD-XAS) measurements were performed on PbI₂, PbBr₂, PbCl₂ as well as NH₃CH₃PbI_xCl_3−x at the Pb-L₂ edge. The data reveal a clear fine structure in near edge region as opposed to data from total yield fluorescence detected spectra.