Fig. 2

Influence of Cd²⁺ on the performance of the NBG perovskite solar cells. a–e Cross-sectional SEM images of NBG PSCs without Cd²⁺ ions in different thicknesses of 370 nm (a), 580 nm (b), 820 nm (c), 1000 nm (d) and 1140 nm (e), respectively. The scale bar is 1 µm in all images. f J–V characteristics of Cd-free NBG PSCs with different perovskite film thicknesses. g J–V characteristics of NBG PSCs with vary molar ratio of Cd²⁺ ions. h and i J–V characteristics (h) and EQE spectra (i) of NBG PSCs that was added with 0.03 mol% Cd²⁺ ions in different perovskite thicknesses. Source data are provided as a Source Data file