title: Dynamic Growth of Pinhole-Free Conformal CH3NH3PbI3 Film for Perovskite Solar Cells.
abstract: Two-step dipping is one of the popular low temperature solution methods to prepare organic-inorganic halide perovskite (CH3NH3PbI3) films for solar cells. However, pinholes in perovskite films fabricated by the static growth method (SGM) result in low power conversion efficiency (PCE) in the resulting solar cells. In this work, the static dipping process is changed into a dynamic dipping process by controlled stirring PbI2 substrates in CH3NH3I isopropanol solution. The dynamic growth method (DGM) produces more nuclei and decreases the pinholes during the nucleation and growth of perovskite crystals. The compact perovskite films with free pinholes are obtained by DGM, which present that the big perovskite particles with a size of 350 nm are surrounded by small perovskite particles with a size of 50 nm. The surface coverage of the perovskite film is up to nearly 100%. Such high quality perovskite film not only eliminated pinholes, resulting in reduced charge recombination of the solar cells, but also improves the light harvesting efficiency. As a result, the PCE of the perovskite solar cells is increased from 11% for SGM to 13% for DGM.
authors.affiliation: Institute of Advanced Materials and Technology, University of Science and Technology Beijing , Beijing, 100083, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.affiliation: Institute of Advanced Materials and Technology, University of Science and Technology Beijing , Beijing, 100083, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Tian
authors.affiliation: Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing, 100083, China.
authors.forename: Lixue
authors.initials: L
authors.lastname: Guo
authors.affiliation: Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing, 100083, China.
authors.forename: Chengbin
authors.initials: C
authors.lastname: Fei
authors.affiliation: Institute of Advanced Materials and Technology, University of Science and Technology Beijing , Beijing, 100083, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Shen
authors.affiliation: Institute of Advanced Materials and Technology, University of Science and Technology Beijing , Beijing, 100083, China.
authors.forename: Xuanhui
authors.initials: X
authors.lastname: Qu
authors.affiliation: Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences , Beijing, 100083, China.|Department of Materials and Engineering, University of Washington , Seattle, Washington 98195-2120, United States.
authors.forename: Guozhong
authors.initials: G
authors.lastname: Cao
keywords: CH3NH3PbI3 film; dynamic growth; perovskite solar cells; surface coverage; two-step dipping process