Extended Data Fig. 1: Characterization of interactions between PVK, PEIE and perovskite films.
From: Maximizing perovskite electroluminescence with ordered 3D/2D heterojunction
a, 1D GIWAXS patterns of PVK film on ITO substrate. Inset, an enlarged view of the region in the green circle in Fig. 1a, showing a distinct diffraction peak. b, FTIR spectra of PVK, PEIE and PVK/PEIE. The OH stretching peak of PEIE shifts by 73.5 cm−1 after reacting with PVK, indicating the formation of hydrogen bonds between PEIE and the PVK layer. c, 1D GIWAXS patterns of PVK/PEIE film on ITO substrate. d, FTIR spectra of PVK/PEIE, pure perovskite on glass substrate and target perovskite. The peak at 1,043.3 cm−1, attributed to the C–O bond, shifts to a lower wavenumber after reacting with the perovskite, suggesting a chemical interaction between PEIE and Pb2+ ions in the perovskite. e, Photographs of PEABr, FABr and PbBr2 DMSO solution after dropping the PEIE solution. f, XPS spectra of Pb 4f. For the XPS measurements, perovskite precursors were spin coated on the PVK and PVK/PEIE substrates and then rinsed with DMSO to confirm the coordination interaction between PEIE and Pb2+ ions.
