Fig. 3: Capture carrier transport with photoluminescence (PL) imaging.

a Polarized optical microscope image, (b) PL intensity image and (c) composite image of a MAPbI3 multi-crystal with GBs. The blue dashed line indicates the position of GB. d Polarized optical microscope image, (e) PL intensity image and (f) composite image of a MAPbI3 single crystal with TBs. The PL excitation position is indicated by the blue circle.