Efficient and Stable CF3PEAI-Passivated CsPbI3 QDs toward Red LEDs

Zhenyu Wang; Xinyu Shen; Chengyuan Tang; Xin Li; Junhua Hu; Jinyang Zhu; William W Yu; Hongwei Song; Xue Bai

doi:10.1021/acsami.1c19685

Efficient and Stable CF₃PEAI-Passivated CsPbI₃ QDs toward Red LEDs

ACS Appl Mater Interfaces. 2022 Feb 16;14(6):8235-8242. doi: 10.1021/acsami.1c19685. Epub 2022 Feb 4.

Authors

Zhenyu Wang¹, Xinyu Shen¹, Chengyuan Tang¹, Xin Li¹, Junhua Hu², Jinyang Zhu², William W Yu³, Hongwei Song¹, Xue Bai¹

Affiliations

¹ State Key Laboratory of Integrated Optoelectronics and College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
² Key Laboratory of Materials Physics of Ministry of Education, Department of Physics and Engineering, Zhengzhou University, Zhengzhou 450052, China.
³ Department of Chemistry and Physics, Louisiana State University, Shreveport, Louisiana 71115, United States.

PMID: 35119813
DOI: 10.1021/acsami.1c19685

Abstract

Oleylamine and oleic acid are common organic capping ligands used in the hot injection preparation of perovskite quantum dots (QDs). Their labile nature is responsible for the poor colloidal stability and conductivity that affect the performance of perovskite QD light-emitting diodes (LEDs). We introduced 4-trifluoro phenethylammonium iodide (CF₃PEAI) directly in the synthesis and found that CF₃PEAI efficiently modified the I^- vacancy defects on the QD surface and partially substituted the surface capping ligand oleylamine. The strong electron pulling ability of F in CF₃PEAI results in a more positive -NH₃⁺ terminal compared to that of PEAI, which promotes tight bonding of CF₃PEAI on the surface of CsPbI₃ QDs. As a result, we achieved bright QDs with a photoluminescence quantum yield of 92% and efficient red LEDs. The maximal luminance was improved to 4550 cd m^-2 for 685 nm red light, which was nearly 4.6-fold of the LEDs with plain CsPbI₃ QDs. Additionally, the peak external quantum efficiency reached 12.5%.

Keywords: LED; defect passivation; ligand exchange; perovskite nanocrystal; red light.