You can see the following links:

1. Chapter Defects in Perovskites for Solar Cells and LEDs

2. https://pv-magazine-usa.com/2021/11/29/the-good-the-bad-and-the-ugly-defects-in-perovskite-solar-cells/

3. https://www.nature.com/articles/s41528-018-0035-z

Dear Romana,

Please refer to the following useful links in order to broaden your understanding about defects in perovskites:

1. https://doi.org/10.1038/nenergy.2016.149

2.Article Defects chemistry in high-efficiency and stable perovskite solar cells

3.Article Origin, Influence, and Countermeasures of Defects in Perovsk...

Regards,

Usman Ali Shah

Perovskite materials have defect tolerance because these materials mostly form defect states within the valence band or conduction band. ... Defect states within the valence band or conduction band arises due to very unusual band structure of perovskite materials.