Ultra‐Thin Atomic Layer Deposited–Nb2O5 as Electron Transport Layer for Co‐Evaporated MAPbI3 Planar Perovskite Solar Cells

Herein, the performance of atomic layer deposited (ALD)-Nb2O5 is compared with existing standard electron transport layer (ETL) configuration in planar n-i-p perovskite solar cell architectures. By making use of a co-evaporated perovskite absorber layer, electron transport materials, such as phenyl-C61-butyric acid methyl ester (PCBM), TiO2, and Nb2O5, are compared in stand-alone and bilayer configurations. The device performance in terms of hysteresis, scan rate dependency, and stability is associated with ETL-perovskite interactions and ALD-Nb2O5 fabricated using a PCBM interfacial layer exhibits superior behavior on all fronts. Using an atomic layer deposition technique can drastically reduce the process temperatures, resulting in conformal Nb2O5 suitable for evaporated perovskite absorbers with promise toward using them in flexible applications.