Lead Halide Residue as a Source of Light Induced Reversible Defects in Hybrid Perovskite Layers and Solar Cells

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A clear signature of deep defects in at least the 1 ppm range is observed by low absorptance photocurrent spectroscopy. An efficiency drop, together with the defects, appears after minutes-long blue illumination and disappears after 1 h or more in the dark. This is caused by the lead halide residual phase inherently present in material prepared by the two-step method. Lead halide decomposes into metallic lead and mobile iodine, which diffuses into the perovskite, producing interstitial defects.

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Description
Defects in CH3NH3PbI3 due to illumination observed by FTPS below absorption edge and effect on efficiency

 

Contact: Jakub Holovský
Collaborating institutions: CTU Faculty of Electrical Engineering