Simultaneous Strontium Doping and Chlorine Surface Passivation Improve Luminescence Intensity and Stability of CsPbI3 Nanocrystals Enabling Efficient Light‐Emitting Devices

A method is proposed to improve the photo/electroluminescence efficiency and stability of CsPbI3 perovskite nanocrystals (NCs) by using SrCl2 as a co‐precursor. The SrCl2 is chosen as the dopant to synthesize the CsPbI3 NCs. Because the ion radius of Sr2+ (1.18 Å) is slightly smaller than that of Pb...

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Bibliographic Details
Published in:Advanced materials (Weinheim) 2018-12, Vol.30 (50), p.e1804691-n/a
Main Authors: Lu, Min, Zhang, Xiaoyu, Zhang, Yu, Guo, Jie, Shen, Xinyu, Yu, William W., Rogach, Andrey L.
Format: Article
Language:English
Subjects:
cesium lead iodide
Chemical synthesis
Chlorine
Doping
Electroluminescence
light‐emitting devices
Luminous intensity
Nanocrystals
Passivity
perovskite nanocrystals
Perovskites
Photoluminescence
strontium chloride
Surface defects
surface passivation
Surface stability
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Summary:A method is proposed to improve the photo/electroluminescence efficiency and stability of CsPbI3 perovskite nanocrystals (NCs) by using SrCl2 as a co‐precursor. The SrCl2 is chosen as the dopant to synthesize the CsPbI3 NCs. Because the ion radius of Sr2+ (1.18 Å) is slightly smaller than that of Pb2+ (1.19 Å) ions, divalent Sr2+ cations can partly replace the Pb2+ ions in the lattice structure of perovskite NCs and cause a slight lattice contraction. At the same time, Cl− anions from SrCl2 are able to efficiently passivate surface defect states of CsPbI3 nanocrystals, thus converting nonradiative trap states to radiative states. The simultaneous Sr2+ ion doping and surface Cl− ion passivation result in the enhanced photoluminescence quantum yield (up to 84%), elongated emission lifetime, and improved stability. Sr2+‐doped CsPbI3 NCs are employed to produce light‐emitting devices with a high external quantum yield of 13.5%. SrCl2 is introduced as a co‐precursor in the synthesis of CsPbI3 perovskite nanocrystals to realize their simultaneous Sr2+ cation doping and surface Cl− anion passivation. The stability of the nanocrystals is improved, and light‐emitting devices with a high external quantum efficiency of 13.5% are realized.
ISSN:0935-9648
1521-4095
DOI:10.1002/adma.201804691