Photoluminescence spectra of perovskite samples with varying crystallization conditions. (a) Photoluminescence spectra of samples similar to those described in Section 3.1, with varying annealing temperature. (b) Photoluminescence spectra of samples similar to those described in Section 3.2, with varying concentration of passivation solution. “Antisolvent” refers to the perovskite film on MeO-2PACz. (c) Peak intensity and peak position when fitting the photoluminescence spectrum with two Gaussian components.