title: Understanding the Cubic Phase Stabilization and Crystallization Kinetics in Mixed Cations and Halides Perovskite Single Crystals.
abstract: The spontaneous α-to-δ phase transition of the formamidinium-based (FA) lead halide perovskite hinders its large scale application in solar cells. Though this phase transition can be inhibited by alloying with methylammonium-based (MA) perovskite, the underlying mechanism is largely unexplored. In this Communication, we grow high-quality mixed cations and halides perovskite single crystals (FAPbI3)1-x(MAPbBr3)xto understand the principles for maintaining pure perovskite phase, which is essential to device optimization. We demonstrate that the best composition for a perfect α-phase perovskite without segregation is x = 0.1-0.15, and such a mixed perovskite exhibits carrier lifetime as long as 11.0 μs, which is over 20 times of that of FAPbI3single crystal. Powder XRD, single crystal XRD and FT-IR results reveal that the incorporation of MA+is critical for tuning the effective Goldschmidt tolerance factor toward the ideal value of 1 and lowering the Gibbs free energy via unit cell contraction and cation disorder. Moreover, we find that Br incorporation can effectively control the perovskite crystallization kinetics and reduce defect density to acquire high-quality single crystals with significant inhibition of δ-phase. These findings benefit the understanding of α-phase stabilization behavior, and have led to fabrication of perovskite solar cells with highest efficiency of 19.9% via solvent management.
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Li-Qiang
authors.initials: LQ
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Zi-Ang
authors.initials: ZA
authors.lastname: Nan
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Hai-Xin
authors.initials: HX
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Tan
authors.initials: T
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Dong-Ping
authors.initials: DP
authors.lastname: Zhan
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Bing-Wei
authors.identifier: 0000-0002-9015-0162
authors.initials: BW
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, iChEM, Xiamen University , Xiamen 361005, China.
authors.forename: Zhong-Qun
authors.identifier: 0000-0002-9775-8189
authors.initials: ZQ
authors.lastname: Tian