Energy Level Matching and Band Edge Reconfiguration for Enhanced Charge Transport in Dion-Jacobson 3D/2D Perovskite Heterojunctions

Generally,the 2D CsPbI3 layer capping on 3D counterpartshas been considered as an effective strategy for both enhancing photovoltaicefficiency and stability. However, the intrinsically poor out-of-planecharge transport through the 2D layer remarkably hinders the overallperformance of solar devices. To overcome such a challenge, we reportthe rationally designed 3D-CsPbI3/2D-(PY n )PbI4 (n = 1-4) heterojunctionswith desirable energy level matching. It is evidenced that the valenceband (VB) edge reconfiguration would occur with the increase of n, accompanied by the VB maximum (VBM) of the 2D componentmoving down from the higher level above that of the 3D component tothe underneath. Consequently, the as-constructed 3D/2D-(PY n )PbI4 (n = 1, 2) heterojunctionsexhibit optimal energy level matching, with accelerated transportof holes from 3D to 2D component and limited backflow of electrons.These findings might provide some meaningful insights on the energylevel matching in 3D/2D perovskite heterojunctions.

Automated summary

The energy level matching in 3D/2D perovskite heterojunctions can be optimized by the rationally designed 3D-CsPbI3/2D-(PY n )PbI4 (n = 1-4) heterojunctions, which can accelerate the migration of electrons from 3D to 2D and limit the backflow of electrons. These findings might provide some meaningful insights on the energy level matching in 3D/2D perovskite heterojunctions.