title: Multichannel Interdiffusion Driven FASnI3Film Formation Using Aqueous Hybrid Salt/Polymer Solutions toward Flexible Lead-Free Perovskite Solar Cells.
abstract: Tin (Sn)-based perovskites are increasingly attractive because they offer lead-free alternatives in perovskite solar cells. However, depositing high-quality Sn-based perovskite films is still a challenge, particularly for low-temperature planar heterojunction (PHJ) devices. Here, a "multichannel interdiffusion" protocol is demonstrated by annealing stacked layers of aqueous solution deposited formamidinium iodide (FAI)/polymer layer followed with an evaporated SnI2layer to create uniform FASnI3films. In this protocol, tiny FAI crystals, significantly inhibited by the introduced polymer, can offer multiple interdiffusion pathways for complete reaction with SnI2. What is more, water, rather than traditional aprotic organic solvents, is used to dissolve the precursors. The best-performing FASnI3PHJ solar cell assembled by this protocol exhibits a power conversion efficiency (PCE) of 3.98%. In addition, a flexible FASnI3-based flexible solar cell assembled on a polyethylene naphthalate-indium tin oxide flexible substrate with a PCE of 3.12% is demonstrated. This novel interdiffusion process can help to further boost the performance of lead-free Sn-based perovskites.
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, 710049, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xi
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, 710049, China.|Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
authors.forename: Zhaoxin
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, 710049, China.|Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Jiao
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, 710049, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Dong
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, 710049, China.
authors.forename: Chenxin
authors.initials: C
authors.lastname: Ran
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, 710049, China.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Piao
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, 710049, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Lei
authors.affiliation: Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
authors.forename: Tze-Bin
authors.initials: TB
authors.lastname: Song
authors.affiliation: Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
authors.forename: Weijun
authors.initials: W
authors.lastname: Ke
authors.affiliation: Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.|Mitsubishi Chemical Group Science & Technology Research Center, Inc., 1000 Kamoshida-cho, Aoba-ku, Yokohama, 227-8502, Japan.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, School of Electronic and Information Engineering, Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, 710049, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Hou
authors.affiliation: Department of Materials Science and Engineering, and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis
keywords: aqueous hybrid solutions; crystallization inhibitor; flexible devices; formamidinium tin iodide; multichannel interdiffusion