title: Crystallization of a perovskite film for higher performance solar cells by controlling water concentration in methyl ammonium iodide precursor solution.
abstract: An optimal small amount of water added into methyl ammonium iodide (MAI) solution in isopropyl alcohol (IPA) helps perovskite crystallization and leads to larger grain size from sequential deposition of perovskite films. The concentration of water was varied from 1% to 7% (vol% of IPA) in MAI solution and optical absorption, crystallization, morphology of perovskite films and their photovoltaic performance were studied in perovskite solar cells. 5% by volume was found to lead to preferential crystallization in the (110) plane with grain size about three times that of perovskite films prepared without adding water into the MAI solution. The optimal water concentration of 5% by volume in the MAI solution led to average perovskite grain size of ∼600 nm and solar cell efficiency of 12.42% at forward scan with a rate of 0.5 V s(-1). Device performance decreases after increasing water concentration beyond 5% in the MAI solution due to formation of the PbI2 phase. Transient photocurrent and photovoltage measurements show the shortest charge transport time at 0.99 μs and the longest charge carrier life time at 13.6 μs for perovskite films prepared from 5% water in MAI solution, which improved perovskite solar cell efficiency from 9.04% to 12.42%.
authors.affiliation: Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA. Qiquan.Qiao@sdstate.edu.
authors.forename: Nirmal
authors.initials: N
authors.lastname: Adhikari
authors.affiliation: Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA. Qiquan.Qiao@sdstate.edu.
authors.forename: Ashish
authors.initials: A
authors.lastname: Dubey
authors.affiliation: Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA. Qiquan.Qiao@sdstate.edu and Department of Physics, Faculty of Science, Damietta University, Egypt.
authors.forename: Eman A
authors.initials: EA
authors.lastname: Gaml
authors.affiliation: Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA. Qiquan.Qiao@sdstate.edu.
authors.forename: Bjorn
authors.initials: B
authors.lastname: Vaagensmith
authors.affiliation: Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA. Qiquan.Qiao@sdstate.edu.
authors.forename: Khan Mamun
authors.initials: KM
authors.lastname: Reza
authors.affiliation: Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA. Qiquan.Qiao@sdstate.edu.
authors.forename: Sally Adel Abdelsalam
authors.initials: SA
authors.lastname: Mabrouk
authors.affiliation: Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA. Qiquan.Qiao@sdstate.edu.
authors.forename: Shaopeng
authors.initials: S
authors.lastname: Gu
authors.affiliation: Shanghai Electrochemical Energy Devices Research Center, School of Chemistry and Chemical Engineering and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, P. R. China. zaijiantao@sjtu.edu.cn xfqian@sjtu.edu.cn.
authors.forename: Jiantao
authors.initials: J
authors.lastname: Zai
authors.affiliation: Shanghai Electrochemical Energy Devices Research Center, School of Chemistry and Chemical Engineering and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, P. R. China. zaijiantao@sjtu.edu.cn xfqian@sjtu.edu.cn.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Qian
authors.affiliation: Center for Advanced Photovoltaics, Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, SD 57007, USA. Qiquan.Qiao@sdstate.edu.
authors.forename: Qiquan
authors.initials: Q
authors.lastname: Qiao