Revealing the Aging Effect of Metal-Oleate Precursors on the Preparation of Highly Luminescent CsPbBr3 Nanoplatelets

Qiugui Zeng; Yiying Du; Jiexuan Jiang; Qian Yu; Yanbo Li

doi:10.1021/acs.jpclett.1c00300

Revealing the Aging Effect of Metal-Oleate Precursors on the Preparation of Highly Luminescent CsPbBr₃ Nanoplatelets

J Phys Chem Lett. 2021 Mar 18;12(10):2668-2675. doi: 10.1021/acs.jpclett.1c00300. Epub 2021 Mar 10.

Authors

Qiugui Zeng¹, Yiying Du¹, Jiexuan Jiang¹, Qian Yu¹, Yanbo Li¹

Affiliation

¹ Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China.

PMID: 33689369
DOI: 10.1021/acs.jpclett.1c00300

Abstract

Due to the ultrafast crystallization process in the triple-source ligand-assisted reprecipitation (TSLARP) technique the [L_yPbBr_x] octahedra is easily distorted, resulting in anisotropic two-dimensional nanoplatelets (NPLs) with low photoluminescence quantum yield (PLQY) and poor stability. Unexpectedly, we obtain CsPbBr₃ NPLs with PLQY approaching unity and high stability using the TSLARP technique through aging the metal-oleate precursors. We find that the significant enhancement of the PLQY is related to the change of solution chemistry of the Pb-oleate precursor in the aging process. While hybrid CsPbBr₃@Cs₄PbBr₆ NPLs with low PLQY (28%) are formed with fresh Pb-oleate precursor, phase-pure CsPbBr₃ NPLs with PLQY of 97.4% are obtained with the aged Pb-oleate precursor. A model that takes into account the transformation of the Pb-oleate in toluene from isolated molecules into clusters after aging is proposed to explain the phenomenon. Our finding highlights the importance of understanding the solution chemistry for the synthesis of the highly luminescent NPLs and provides a new way to break the "blue-wall" in perovskite light-emitting devices.