Figure 7.

Energy level profile of perovskite solar cells. (a) Energy profile of the widely used materials of PSC with variable HTL. It shows the order of energy required to move electrons in an ETL and holes in HTL sides from the active layer. (b) Possible position of all the constituents of PSC with HOMO and LUMO. (c) the comparative energy level diagram of widely used ETLs (SnO2, ZnO, and TiO₂) with an allotrope of Carbon (T-carbon) and different active materials (MAPbI₃, FAPbI₃, MAPbBr₃, and (AA)₂Pb I₃) used in PSC. This diagram provides a clear picture of T-carbon, which has the same energy as most TiO2 and is considered a promising electron transporter [18].