Tantalum-Doped TiO<sub>2</sub> Prepared by Atomic Layer Deposition and Its Application in Perovskite Solar Cells
Chia-Hsun Hsu,
Ka-Te Chen,
Ling-Yan Lin,
Wan-Yu Wu,
Lu-Sheng Liang,
Peng Gao,
Yu Qiu,
Xiao-Ying Zhang,
Pao-Hsun Huang,
Shui-Yang Lien,
Wen-Zhang Zhu
Affiliations
Chia-Hsun Hsu
School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
Ka-Te Chen
School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
Ling-Yan Lin
Key Laboratory of Green Perovskites Application of Fujian Province Universities, Fujian Jiangxia University, Fuzhou 350108, China
Wan-Yu Wu
Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan
Lu-Sheng Liang
CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
Peng Gao
CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Provincial Key Laboratory of Nanomaterials, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
Yu Qiu
Key Laboratory of Green Perovskites Application of Fujian Province Universities, Fujian Jiangxia University, Fuzhou 350108, China
Xiao-Ying Zhang
School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
Pao-Hsun Huang
School of Information Engineering, Jimei University, Xiamen 361021, China
Shui-Yang Lien
School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
Wen-Zhang Zhu
School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
Tantalum (Ta)-doped titanium oxide (TiO2) thin films are grown by plasma enhanced atomic layer deposition (PEALD), and used as both an electron transport layer and hole blocking compact layer of perovskite solar cells. The metal precursors of tantalum ethoxide and titanium isopropoxide are simultaneously injected into the deposition chamber. The Ta content is controlled by the temperature of the metal precursors. The experimental results show that the Ta incorporation introduces oxygen vacancies defects, accompanied by the reduced crystallinity and optical band gap. The PEALD Ta-doped films show a resistivity three orders of magnitude lower than undoped TiO2, even at a low Ta content (0.8–0.95 at.%). The ultraviolet photoelectron spectroscopy spectra reveal that Ta incorporation leads to a down shift of valance band and conduction positions, and this is helpful for the applications involving band alignment engineering. Finally, the perovskite solar cell with Ta-doped TiO2 electron transport layer demonstrates significantly improved fill factor and conversion efficiency as compared to that with the undoped TiO2 layer.
