Fig. 5: Charge carrier dynamics in MAPbI3 with point defects.
Shown are populations of the excited state (ES) with electron and hole at the band edges, and the ground state (GS), following photoexcitation of the defect states in MAPbI3 with (a) MAI, (b) Pbi and (c) Ii defects. The corresponding data for the Iv defect are shown in Fig. 6d. Sub-bandgap excitation of MAI, Ii and Iv defect levels results in energy up-conversion and charges escaping into bands, as indicated by growth of the ES population, because the defect levels fluctuate between shallow and deep regimes, Fig. 2a, c, d. In contrast, populating the Pbi defect results in charge recombination, i.e., growth of the GS population, because the Pbi defect always remains deep, Fig. 2b.
