Fig. 5: Parameters values, radiative species density and equilibrium population as resulted from differential rate equations.

a Trap states density (red) and excitons gemination rate (blue) versus exposure time. Vertical bars are related to the values range of K_X and N_T parameters for which the simulation curves well describe time-resolved photoluminescence (TRPL) traces for each exposure time while the error bars of exposure time are within the markers size. b Excitons gemination rate versus trap states density. Continuous line represents the theoretical excitons gemination rate as calculated by Langevin and scattering limited mobility models for a net charge value of Z = 1 (red line) and Z = 2 (purple line); grey line represents the best fitting-curve of the experimental data, resulting in an average value of Z = 1.6, indicating a larger dominion of Z = 2 ionic traps than Z = 1 ones. The bars are related to the values range of K_X and N_T parameters for which the simulation curves well describe time-resolved photoluminescence (TRPL) traces for each exposure time. c Excitons, electrons and holes density fractions versus passivation time after 20 ns from laser pulse. The grey line, labeled as Saha equilibrium, indicates the exciton density as extracted by Saha equation for a photogenerated carrier density value of n₀ = 6 × 10¹⁵ cm⁻³. n_k reported in the y axis stay for electrons n_e, holes n_h and excitons n_X populations. The error bars are within the markers size. d Equilibrium population versus trap states density as extracted by the electrons n_e, holes n_h and excitons n_X populations taken from time-resolved photoluminescence fits at different times after laser pulse (from 20 to 50 ns). Red and purple lines represent the theoretical equilibrium density calculated by the ratio k_DX/k_X (where k_X and k_DX are the excitons gemination/dissociation rate, respectively) as extracted by the time-resolved photoluminescence fit against the trap density by using modified Langevin model. The grey line, labeled as Saha equilibrium, indicates the equilibrium population as extracted by Saha equation for n₀ = 6 × 10¹⁵ cm⁻³. The black line represents the photogenerated carrier density. Horizontal bars are related to the values range of N_T parameter for which the simulation curves well describe time-resolved photoluminescence (TRPL) traces for each exposure time while the vertical error bars are within the markers size.