Figure 3. Radiative recombination in perovskites.

(a) Initial transient PL signal (time integrated for 2 ns after excitation with a 100 fs laser pulse) plotted over the initial charge carrier density. We observe a quadratic scaling in n in all three material compositions. (b) Total (black) and radiative (blue) recombination rate dependence on charge carrier density n. The radiative recombination rates were derived by plotting the transient PL signal over the TA signal at the same time delay. The radiative recombination rate scales quadratically with carrier density even in regimes where the total recombination rate is linear (below 2 × 10¹⁶ cm⁻³) and cubic (above 2 × 10¹⁸ cm⁻³) in excitation density. We conclude that the radiative recombination is bimolecular and that linear and cubic recombination rates have their origin in non-radiative processes.