fig7

Figure 7. Photovoltaic performance of PSCs. (A) Cross-sectional SEM images; (B) J-V curves under 1 sun illumination; (C) PCE statistics; (D) Nyquist plots in the dark; (E) EQE spectra; (F) OCVD curves; (G) Dark J-V curves for control, AA-, ABA-, and DBA-modified devices. PSCs: Perovskite solar cells; SEM: scanning electron microscopy; PCE: power conversion efficiency; EQE: external quantum efficiency; OCVD: open-circuit voltage decay; AA: L-aspartic acid; ABA: 4-aminobutyric acid; DBA: L-2,4-diaminobutyric acid; Spiro-OMeTAD: 2,2’,7,7’-tetrakis(N,N-di-p-methoxyphenylamine)-9,9’-spirobifluorene; ITO: indium tin oxide.