Fig. 3: Understanding the halide redistribution during VAC-process.
From: Mixed halide perovskites for spectrally stable and high-efficiency blue light-emitting diodes
a, b PL evolution of the precursor films kept in the glovebox atmosphere (a) and DMF atmosphere (b) with time. c the evolution of emission linewidth and the proportion of P2 (AP2) to the respective total area of the emission band (A) in VAC-treated films with time. d Schematic illustration of the proposed mechanism for halide redistribution. Here, the purple Pb(Br/Cl)64− octahedra represent chloride-rich phases in respect to that with stoichiometric bromide/chloride distribution (blue octahedra). The khaki represents the liquid phase within the films and the blue arrows represent ion exchange process. The excessive ions within the dried films are not illustrated for clarity. e, f The evolution of CIE coordinates upon bias (e) and peak EQEs of the devices with varying duration of VAC-treatment (0, 1, 2, 5, 20 min). f The error bars present the standard deviation extracted from 4 to 6 devices.
