Fig. 5: Energetic disorder landscape.
a Steady-state ultraviolet-visible (UV-vis) absorption spectra of CsPbI2Br nanoplate and CsPbI2Br/WSe2 heterostructure. b The Tauc plots of absorption spectra for extracting the optical bandgap of CsPbI2Br nanoplate and CsPbI2Br/WSe2 heterostructure. The dashed purple lines are Tauc plots for determining the optical bandgap. c Logarithm of absorption coefficient versus photon energy to calculate Urbach energy (EU) of CsPbI2Br nanoplate and CsPbI2Br/WSe2 heterostructure. The dashed purple lines mark the sub-bandgap absorption where Urbach energies are extracted. d, e Spectro-temporal transient absorption maps for CsPbI2Br nanoplate and CsPbI2Br/WSe2 heterostructure. The dashed arrow is a guide to the eye for highlighting the spectra shift over time. f The shifts of peak position of transient bleach over time for CsPbI2Br nanoplate and CsPbI2Br/WSe2 heterostructure. The symbols represent the experimental values, and the solid lines are fits to an exponential decay function. g, h Spectro-temporal transient reflectance maps for CsPbI2Br nanoplate and CsPbI2Br/WSe2 heterostructure. The black curves are corresponding typical spectra cuts at 5 ps. i The surface carrier decay kinetics extracted from the TR spectra of CsPbI2Br/WSe2 heterostructure and CsPbI2Br nanoplate and respective fitting to the diffusion-surface recombination model. The red dots and black dots represent experimental data, and the red line and black line correspond to their fitting results.
