Dresden 2017 – wissenschaftliches Programm
CPP 13.26: Poster
Montag, 20. März 2017, 18:30–21:00, P1A
High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy on Lead Halide Perovskite Precursors — •Pascal Becker1,2, 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 NH3CH3PbIxCl3−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.