Low-temperature processed tantalum/niobium co-doped TiO <sub>2</sub> electron transport layer for high-performance planar perovskite solar cells
Yanyan Duan, Gen Zhao, Xiaotao Liu, Jiale Ma, Shuyao Chen, Yanlin Song, Xiaodong Pi, Xuegong Yu, Deren Yang, Yiqiang Zhang, Feng Guo
Abstract
Abstract A low-temperature preparation process is significantly important for scalable and flexible devices. However, the serious interface defects between the normally used titanium dioxide (TiO 2 ) electron transport layer (ETL) obtained via a low-temperature method and perovskite suppress the further improvement of perovskite solar cells (PSCs). Here, we develop a facile low-temperature chemical bath method to prepare a TiO 2 ETL with tantalum (Ta) and niobium (Nb) co-doping. Systematic investigations indicate that Ta/Nb co-doping could increase the conduction band level of TiO 2 and could decrease the trap-state density, boosting electron injection efficiency and reducing the charge recombination between the perovskite/ETL interface. A superior power conversion efficiency of 19.44% can be achieved by a planar PSC with a Ta/Nb co-doped TiO 2 ETL, which is much higher than that of pristine TiO 2 (17.60%). Our achievements in this work provide new insights on low-temperature fabrication of low-cost and highly efficient PSCs.