Fig. 8
From: Origin of apparent light-enhanced and negative capacitance in perovskite solar cells
Sketch explaining ion-enhanced charge-carrier injection at the contact. Here the n-side is shown. An analogous picture can be drawn for the p-side. Ion redistribution upon increasing the voltage by ΔV changes the injection barrier ϕB. More positive net ionic charge leads to a surface dipole that decreases ϕB. This effect enhances the current, which appears as a negative capacitance
