Spray-Pyrolyzed Tantalium-Doped TiO2Compact Electron Transport Layer for UV-Photostable Planar Perovskite Solar Cells Exceeding 20% Efficiency

The electron-transporting layer (ETL) material is one of the critical components of the n-i-p planar perovskite solarcells (PSCs). TiO2is the most typically used ETL material;however, low electron mobility and conductivity of TiO2limit theperformance of the cells. Ion doping is an effective method forimproving the electrical properties of TiO2films. In this study, pureand tantalum (Ta)-doped TiO2films, fabricated with the spraypyrolysis method, were employed as the ETL in the n-i-p planarPSCs. Ta doping improved the electrical conductivity anddecreased interface defect between the TiO2electron transportand perovskite layers, promoting efficient electron transfer at theinterface. After dopant optimization of transport layers, the overallpower conversion efficiency was increased to as high as 20.45%with negligible hysteresis exceeding the previous highest efficiency recorded for Ta-doped TiO2ETL-based PSCs. More importantly,Ta-doped TiO2ETL-based PSCs exhibited an admissible photostability under continuous illumination including UV radiation andretained 65% of their initial efficiency over 300 h in the ambient environment, higher than that of 50% for the control device. These findings indicated that spray-pyrolyzed Ta-doped TiO2films could be a promising compact layer to fabricate highly efficient and UV-stable planar PSCs in large-scale manufacturing

Automated summary

Ta-doped TiO2 films improve the electrical properties and promote efficient electron transfer of perovskite solar cells, while also exhibiting high photostability.