Effect of Modulating Spin-Coating Rate of TiO₂ Precursor for Mesoporous Layer on Hysteresis of Solar Cells with Polar CH₃NH₃PbI₃ Perovskite Thin Film

Figure 4

PFM phase images of the CH₃NH₃PbI₃ perovskite films which applied (0 V, 0 V) (a) w/o mp-TiO₂ layer and (b) with the spin-coating rate of the mp-TiO₂ precursor for 3000 rpm and (c) with the spin-coating rate of the mp-TiO₂ precursor for 1500 rpm. PFM phase images of the CH₃NH₃PbI₃ perovskite films which applied (~8 V, 0 V) (d–f) correspond to those which applied (0 V, 0 V) without mp-TiO₂ layer and with the different spin-coating rates of the mp-TiO₂ layers.

(a)

(b)

(c)

(d)

(e)

(f)