Fig. 3: Analysis of exciton–phonon coupling effects of the four perovskites.
From: Regulation of the luminescence mechanism of two-dimensional tin halide perovskites
Contour map of the temperature-dependent normalized PL spectra: a (PEA)2SnI4, b (BA)2SnI4, c (HA)2SnI4, and d (OA)2SnI4 films obtained under continuous wave (CW) laser excitation at a wavelength of 473 nm, a power density of 2 µJ cm−2, and from 300 to 77 K with 25 K intervals. The color scales represent the intensity of normalized PL. Temperature-dependent FWHM for e (PEA)2SnI4, f (BA)2SnI4, g (HA)2SnI4, and h (OA)2SnI4. The blue dot represents the experimental data, the short lines above and below the blue dots represent the error bars, and the red solid lines represent the fitting results of the exciton–phonon coupling model (3) in Supplementary Note 6. Average atomic displacement Ueq of chemical elements (H, C, N, Sn, and I) in (PEA)2SnI4, (BA)2SnI4, (HA)2SnI4, and (OA)2SnI4 at i 275 K and j 125 K extracted from single-crystal X-ray diffraction (SCXRD) data (Supplementary Information). k Characteristics of the ratio (PTE/PFE) of trapping -state exciton PL intensity to free exciton PL intensity as a function of temperature. l the PLQY of (BA)2PbI4 and (BA)2SnI4 obtained under the same experimental conditions.
