Band engineering at the interface of all-inorganic CsPbI2Br solar cells

However, low efficiency and high moisture sensitivity hinder its advancement. In this work, we exploit 4-bromobenzylamine hydriodate post-treatment on CsPbI2Br thin films to assist the extraction of holes and to block the flow of electrons to the hole transport layer through band engineering at the CsPbI2Br bulk/surface.

We found through depth profile analysis that a small amount of BrBeAI permeates into the CsPbI2Br bulk and mainly locates at the CsPbI2Br grain boundaries. This treatment leads to an improved short-circuit current of CsPbI2Br solar cells and an enhanced efficiency from 13.10% to 14.63%. In addition, the incorporation of the hydrophobic organic component into perovskite films effectively enhances the moisture resistance.