Fig. 1: Structural and compositional characterization of the Ge–Pb perovskite samples.
a The ICP-OES results of Ge molar fraction in thin films versus the intended Ge content in the precursor solution. The error bars represent the estimated experimental errors. b The XRD results of the perovskite films deposited on Si substrates with different Ge molar fractions. c XRD pattern and the corresponding fitting using Rietveld refinement for the perovskite sample with 10 mol% Ge inclusion. The observed profile is marked by black crosses and the calculated profile is represented by the red line. Bragg peak positions of the 3D perovskite CsPb0.9Ge0.1Br3 and 2D perovskite PEA2Pb0.9Ge0.1Br4 are labeled by orange and gray marks, respectively. The difference diffractogram (experimental minus calculated) is shown in light blue. d Refined crystal structure: green octahedra represent Pb(Ge)Br6; Pb or Ge atoms are in the centers of the octahedra; blue-green spheres represent Cs atoms; brown spheres represent Br atoms. e Pseudo-cubic (c′ = c/\(\sqrt{2}\)) lattice parameters variation for 3D perovskite CsPb1−xGexBr3 (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5). The error bars represent the estimated errors. f The STEM-HAADF images showing the structure of the perovskite nanocrystals with 10 mol% Ge inclusion from different regions.
