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X-ray scattering measurements for highly efficient perovskite solar cells


2D GIWAXS detector image recorded at PTB's Four Crystal Monochromator beamline with a photon energy of 8 keV and an incident angle of 1° of a CsPbI1.8Br1.2 perovskite prepared at 60 °C.

Perovskite solar cells (CsPbI3-xBrx) with a low bandgap are an important ingredient in the development of highly efficient tandem solar cells, which layer a perovskite solar cell on top of a silicon solar cell to combine the light harvesting capabilities of both and reach high overall efficiency. The efficiency is vastly influenced by the crystal structure - phase composition and crystal orientation- of the solar cell material. Perovskite cells prepared by the Helmholtz-Zentrum Berlin (HZB) with different annealing protocols have been studied by Physikalisch-Technische Bundesanstalt (PTB) at BESSY II in Berlin-Adlershof.

The GIWAXS (Grazing -Incidence Wide-Angle X-Ray Scattering) measurements demonstrated that the cell material had a varying texture and phase purity, depending on the initial annealing temperature, which explains the different efficiencies of up to 14.6% in the best case. The highest performing cell was composed of a single orthorhombic phase in (110) orientation lying out of plane, whereas the lower performing cell material was composed of a mixture of crystalline phases of different orientation.

The insight from this joint work between HZB and PTB can be used for further optimization of perovskite solar cells concerning overall efficiency and stability.

Publication: Q. Wang et al., Managing Phase Purities and Crystal Orientation for High‐Performance and Photostable Cesium Lead Halide Perovskite Solar Cells, Sol. RRL 2020, 2000213 doi.org/10.1002/solr.202000213


C. Gollwitzer, 7.21, E-Mail: Opens window for sending emailChristian.Gollwitzer(at)ptb.de
D. Skroblin, 7.21, E-Mail: Opens window for sending emailDieter.Skroblin(at)ptb.de