Fig. 26. (a) X-ray diffraction shape of an MAI-PbI₂-DMSO intermediate stage produced by toluene treatment on the layer deposited by spin-coating of MAI-PbI₂-DMSO-GBL solution. (b) SEM image of the subsequent perovskite layer using the middle stage (reproduced with permission from ref. 209 Copyright 2014 NPG).