Nanoscale Graded Nitrogen‐Doping of TiO 2 via Pulsed Laser Deposition for Enhancing Charge Transfer in Perovskite Solar Cells

Abstract An electron transport layer (ETL) for highly efficient perovskite solar cells (PSCs) should exhibit superior electrical transport properties and have its band levels aligned with interfacing layers to ensure efficient extraction of photo‐generated carriers. Nitrogen‐doped TiO 2 (TiO 2 :N) is considered a promising ETL because it offers higher electrical conductivity compared to conventional ETLs made from spray‐pyrolyzed TiO 2 . However, the application of highly doped TiO 2 :N in PSCs is often limited by the misalignment of energy band levels with adjacent layers and reduced optical transparency. In this study, a novel approach is introduced to enhance the charge transport characteristics and accurately align the electronic band alignment of TiO 2 :N layer through nanoscale doping level grading, achieved through the pulsed laser deposition (PLD) technique. The TiO 2 :N ETL with…