Xun Xiao1 Chunxiong Bao2 Yanjun Fang2 Jun Dai3 Benjamin R. Ecker4 Yuze Lin2 Shi Tang2 Ye Liu2 Yehao Deng2 1 Xiaopeng Zheng2 Yongli Gao4 Xiao Cheng Zeng3 Jinsong Huang1 2

1, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
2, Mechanical and Materials Engineering, University of Nebraska–Lincoln, Lincoln, Nebraska, United States
3, Department of Chemistry, University of Nebraska–Lincoln, Lincoln, Nebraska, United States
4, Department of Physics and Astronomy, University of Rochester, Rochester, New York, United States

The surface composition of perovskite films is very sensitive to film process and can deviate from optimal, which generates unfavorable defects and results in efficiency loss in solar cells and slow response speed in photodetectors. An argon plasma treatment is introduced to modify the surface composition by tuning the ratio of organic and inorganic component ratio as well as defects type before deposition of passivating layer and form an ultra-thin n type self-doping layer. It efficiently enhanced the charge collection across the perovskite-electrode interface by suppressing charge recombination. Therefore, perovskite solar cells with argon plasma treatment yield enhanced efficiency to 20.4% and perovskite photodetectors can reach their fastest respond speed which is solely limited by the carrier mobility.