Methanol-induced fast CsBr release results in phase-pure CsPbBr3 perovskite nanoplatelets

Xin Liu; Zhao Luo; Wenxu Yin; Aleksandr P Litvin; Alexander V Baranov; Jiaqi Zhang; Wenyan Liu; Xiaoyu Zhang; Weitao Zheng

doi:10.1039/d0na00123f

Methanol-induced fast CsBr release results in phase-pure CsPbBr₃ perovskite nanoplatelets

Nanoscale Adv. 2020 Mar 23;2(5):1973-1979. doi: 10.1039/d0na00123f. eCollection 2020 May 19.

Authors

Xin Liu¹, Zhao Luo¹, Wenxu Yin¹, Aleksandr P Litvin², Alexander V Baranov², Jiaqi Zhang¹, Wenyan Liu³, Xiaoyu Zhang¹, Weitao Zheng¹

Affiliations

¹ Key Laboratory of Automobile Materials, Ministry of Education, College of Materials Science and Engineering, Jilin University Changchun 130012 P. R. China zhangxiaoyu@jlu.edu.cn wtzheng@jlu.edu.cn.
² Center of Information Optical Technology, ITMO University 49 Kronverksky Pr. St. Petersburg 197101 Russia.
³ College of Materials Science & Engineering, Beihua University Jilin 132013 P. R. China.

Abstract

Formation of a non-emissive wide bandgap CsPb₂Br₅ component often accompanies the synthesis of CsPbBr₃ perovskites, introducing undesired energy states and impeding the charge transport. Here, we demonstrate that a small amount of a methanol additive can promote the CsBr release rate, facilitating CsPbBr₃ formation and suppressing CsPb₂Br₅ formation. Some of the methanol ionizes into CH₅O⁺ and CH₃O^-, which act as surface ligands and change the crystallization environment, inducing shape evolution from spherical nanocrystals to rectangular nanoplatelets (NPLs), leading to monodispersed and phase-pure 8 unit-cell-thick CsPbBr₃ NPLs. Meanwhile, nonradiative recombination processes are inhibited as a result of NPL surface passivation. Bright CsPbBr₃ NPLs with a photoluminescence quantum yield reaching 90% were employed as emitters for electroluminescent light-emitting devices.