Figure 4.

(a) J–V characteristics of a C‐PSC based on a US spray coated CE from −1.5 to 1.5 V measured under dark conditions. (b) Proposed energy band diagram for the FTO/TiO₂/Cs₂AgBiBr₆/CE architecture under flat‐band conditions. Valence and conduction bands values for the perovskite are average values according to literature.[ ⁴⁰ , ⁴³ , ⁶³ , ⁶⁴ ] (c) Lumped equivalent circuit model of the tested PSCs under illumination. (d) Comparison between under illumination J–V data and our model: the black solid line is the measured current; the blue dotted line is the numerical fitting applying the model; the red solid line is a model simulation with R _S=0 Ω.