Effect of Annealing Temperature on Tantalum-Doped TiO2 as Electron Transport Layer in Perovskite Solar Cells

Plasma-enhanced atomic layer deposition is used to fabricate compact tantalum (Ta)-doped titanium oxide (TiO2) thin films as electron transport layers (ETLs) and hole blocking layers for perovskite solar cells (PSCs). The effects of Ta-doped TiO2 with different annealing temperatures on film structure and electronic properties are researched. The experimental results exhibit that the substitutional Ta-doping into TiO2 (Ta content of similar to 1.5%) increases the stability of crystal structure and passivates the material defects, thereby improving the film quality. The annealed Ta-doped TiO2 films have a resistivity of approximately 6.5 Omega.cm which is three orders of magnitude lower than 3.4 x 10(3) Omega.cm of intrinsic TiO2. Finally, the annealing process eliminates the defects, and therefore, improves electron transport for PSCs, leading to a clearly enhanced fill factor (FF) of 0.77 and conversion efficiency of 19.62% when compared to that of undoped TiO2 ETL devices.

Automated summary

The effects of plasma-enhanced atomic layer deposition fabricated Ta-doped TiO2 thin films on film structure and electronic properties are investigated. Ta-doping improves crystal structure stability and passivates material defects, leading to improved film quality. The annealing process enhances electron transport for perovskite solar cells, resulting in increased fill factor and conversion efficiency.