Origin of High Electronic Quality in Structurally Disordered CH3NH3PbI3 and the Passivation Effect of Cl and O at Grain Boundaries

The organic-inorganic hybrid perovskite CH3NH3PbI3 exhibits more structural disorder but more electronic order compared to inorganic CdTe. The grain boundaries of CH3NH3PbI3 could induce defect levels around the VBM and thus increase hole effective mass. CI and O are found to be able to spontaneously segregate into the GBs, passivate the defect state, and improve carrier transportation.