Fig. 2: Pressure-dependent optical properties of Rb6Re6S8I8 during compression.
a Pressure-dependent PL contour plot from 1 atm to 12 GPa, where the PL emission is fully annihilated. b–e Pressure dependences of the PL intensity, PL peak wavelength, and full width at half maximum (FWHM) of the PL peak and second central moments (m2), respectively. Here, for a Gaussian-type emission profile, the FWHM is conveniently quantified by m2 as m2 = (FWHM)2/8ln2, where the error bar in d shows the fitting errors. Note that two individual samples, 1 and 2, were employed to confirm the validity of the experimental results. f Experimental time-resolved PL decays (dots) and fittings (solid lines) from 1 atm to 10.2 GPa. g The extracted carrier lifetimes obtained by fitting the time-resolved PL decay traces in f. h Comparison of the on-off photocurrent response and magnitudes from 1 atm to 24.7 GPa. i Evolution of the photocurrents extracted from (h). j Pressure-dependent UV-vis absorbance near bandgap regions from 1 atm to 30 GPa, where a drastic narrowing of the bandgap can be observed at approximately 17 GPa. Therefore, the onset pressures for abrupt bandgap narrowing, drastic photocurrent increase, and long-range disorder are coincident, thus indicating that structural amorphization is the common origin for the property changes. The sizes of the symbols shown in (b, c, e, g and i)cover the experimental or fitting errors.
