Numerical modelling of ion-migration caused hysteresis in perovskite solar cells

We presented one dimensional defect model to simulate hysteresis in perovskite solar cells. It can be numerically simulated in perovskite devices with p+-i-n+ configuration by considering ions migration under influence of different voltage biasing. The availability of mobile ion which contribute towards ion migration, ion accumulation at interfaces and near interface regions are observed to be generating I–V hysteresis in simulations. To simulate ion migration under positive poling we have taken a defect model and reverse the defect polarity for simulating ion migration under negative poling. The hysteresis is observed when the device has either of the condition (a) defects at the interfacial traps at the junction, or (b) defects in p+ or n+ layer in vicinity of the interface region. Both the conditions have yielded I–V hysteresis when we switched polarity of defect to simulate positive and negative poling. This study brings out the prominent role of mobile ions and carrier dynamics in controlling device working. Band diagram and capacitance variation visibly showed the impacts of charge reversal and capacitance simulations of perovskite device. 1D modelling shows that the ionic migration is one of the responsible mechanisms behind the I–V hysteresis in the perovskite solar cell devices